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CRIME-SCENE INVESTIGATION AND EXAMINATION | Packaging
432 CRIME-SCENE INVESTIGATION AND EXAMINATION/Packaging Kirk P (1974) Crime Investigation, 2nd edn. Chichester: Wiley. Svensson A and Wendel O (1974) Techniques of Crime Scene Investigation, 2nd edn. New York: Elsevier.
Packaging J Horswell, Australian Federal Police, Canberra, Australia Copyright # 2000 Academic Press doi:10.1006/rwfs.2000.0452
Background The ideal method of collecting and subsequent packing of items for transport to the forensic science laboratory will vary considerably depending on the nature of the item concerned. Likewise the material from which a package is fabricated will also vary considerably.
Infested Material In some instances material recovered from crime scenes or mortuaries for return to the forensic science laboratory, or for long-term storage as property, may be infested with pests, such as fleas, lice, maggots or coffin beetles. Care must be taken when examining this material by wearing protective clothing and gloves. If possible, always use a large open search bench. If insect infestation is present within the item there are at least two methods available for killing them: . Place the material and container in a large plastic bag and seal it. Place the bag into a deep freeze until the insects are dead. . Add a few drops of ethyl formate to the plastic bag containing the item and its container. Seal the bag and leave for approximately 1 h or until the insects are dead. Where blood or semen stains are present, samples from stains must be collected prior to freezing. Consideration should also be given to entomological aspects of the case: both live and dead insect specimens may be required for examination.
Collection of Items Paper as a Packaging Medium Generally, the use of paper in the form of bags of various sizes is recommended. Paper bags are fabricated in various sizes and should be readily available. If using envelopes, A4 white bond paper should be employed in the first instance for small items such as hairs, fibers, glass or paint. Place the item onto previously folded paper and then place this in an envelope. This will prevent the loss of items from envelope corners, and the use of folded paper will simplify the subsequent examination under a macroscope. The placement of clothing and biological material in paper allows the item to breath; placement in a plastic bag may result in bacterial action and encourage the growth of mold. All items should be air dried prior to packaging in paper. Extensively blood-stained or semen-stained items recovered from crime scenes should be first placed into paper and then protected by a plastic bag; however, the item must be removed from packaging on arrival at the forensic science laboratory and air dried. Items wet with volatile substances should be placed in nylon bags or new, clean, paint cans. Normal polyethylene bags are not suitable for the retention of volatiles.
Quantity It is better to collect excess material than to have an examination fail because there is insufficient material for analysis. Where difficulty may be encountered in collecting minute traces of substances, specialist collection techniques should be employed. If, however, traces of evidence are on small items and there is a chance of loss, the trace subsample should be recovered and placed into a separate package. If the trace is a stain then the stain should remain on the item for assessment in the forensic science laboratory. This is particularly relevant where the item as a whole is vitally relevant; for example, a blood-stained knife. Controls In many cases involving stained material, for example fire debris, it is necessary to submit unstained material for analysis to determine if the material itself interferes with the analytical procedures. Reference material In any comparison of the constituents of two substances, sufficient reference sample material should be provided. For example, if dust on clothing is suspected of being ballast from a particular safe, a sufficient amount should be collected, packaged and submitted together with the items of clothing in order that a satisfactory comparison may be performed. The reference sample should be repre-
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sentative of the source from which the test sample originated. For example, it is useless attempting to compare a body hair found at the scene with a head hair from the suspect. Similarly, the comparison of soil from a shoe with soil from the scene may be unsuccessful if the sources of the two samples are separated by only a few meters. Labeling
The purpose of a label is twofold: . to identify the nature and source of the item; . to establish a chain of custody. Ideally, a label should have the following information recorded on it: . nature of contents; . source (where found or from who recovered); . date and time; . signature and printed surname of collector; . sequential number; . unique case identifying number. Additionally, room should be available on the label to record the movement of the item. The label should be completed at the time of collection or receipt of the item. If an item is collected from a person, use that person's name; for example, `Trousers from John Smith'. Do not mark the item with the word `Suspect', as this may lead to the exhibit being excluded from a trial. Some courts are of the view that to mark items in this way is `unnecessary' and `objectionable' because whenever such an item is mentioned in evidence during the trial the jury are being told that the accused has been a suspect. This perhaps gives the impression that he or she was a suspect early in the investigation, which need not necessarily be the case. The jury may also wrongly hold the view that there may be more to know about the accused, which could be prejudicial. Obviously the word `offender' should never be used at this is a presumption of guilt. The sequential number used should relate to the collectors item list and could be JH1, JH2, JH3, etc. When making a subsequent examination of the items collected, any material removed should be given a number that relates to the original item. For example a pair of trousers is marked JH1 and hair is recovered from the trousers. This item should be marked JH1.1. In this way each subsample can be traced easily back to the original source item. Where the item is something substantial, for example a knife or clothing, then the exhibit itself should be marked as well as the container. It may be appropriate to tie a label with a piece of string to the item. If this is done then there can be no doubt about later identifying the item in the witness box should it be
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separated from its container. If using plastic pots or vials, ensure that there is a corresponding mark on both the lid and the container to avoid any mixing up of the containers. The sequential number and unique case number are normally used for this purpose. Collection
The proper collection of items and trace material is essential in obtaining the greatest evidential value from an examination. Special clothing should be worn during all scene and laboratory examinations. Scene suits, white cotton overalls or laboratory coats should always be worn as white cotton has the least evidential value as a fiber and is therefore suitable in preventing contamination of scenes or clothing with fibers from the examiner's clothing. There is also an occupational health and safety dimension to the use of appropriate clothing. Collection case
Collection cases must be kept clean, with equipment stored in an orderly manner. The principal collection items and their uses are listed in Table 1.
Collection Techniques A variety of techniques have been developed for the collection of trace material and other potential evidential material. Each technique is designed to prevent damage to, and contamination of, the material. The main collection techniques can be described as: . . . . .
handpicking; tape lifting; swabbing; sweeping; vacuuming.
Handpicking
Whenever examining the crime scene, garments, bodies or other articles, the initial emphasis should be directed toward the collection of gross and macroscopic items that can be recovered by hand or by the use of tweezers. Items large enough to see with the naked eye should be collected by handpicking. Material such as hairs, large paint and glass fragments and pieces of vegetation should be collected before the application of other collection techniques, such as tapelifting, sweeping and vacuuming. Handpicking has the advantage of establishing the position of the material on the item and requires no further time in searching, whereas tapelifts, sweepings and vacuumings have to be further searched to
434 CRIME-SCENE INVESTIGATION AND EXAMINATION/Packaging Table 1 Principal items of collection equipment and their uses Item
Collection use
Scalpel Probe Brush Swab Paint brush Spatula Tweezers (metal) Tweezers (plastic)
Paint smears, visible fibers, vegetation and dried blood Paint, fibers, residues, oils, greases; manipulation of microscopic particles Trace particles: paint, metals, vegetation, glass Small particles, which will be caught in the coarse fibers of the swab To sweep localized and constricted areas Soil samples, whole or partly congealed blood; mixing of casting compound Trace material, such as fibers, hair and vegetation Items that may be damaged if metal tweezers are used; recovery of bullets and fragments during postmortem examinations and for use when recovering blood stains using small pieces of moistened white cotton. Employed where cleaning is not possible and a number are required. Each tweezer is inexpensive therefore can be destroyed after each use Dried blood linen stains once moistened with distilled water Particles of iron and steel, after covering the magnet with plastic
Cotton Magnet
isolate small particulate matter of interest. When collecting items by hand, consideration should be given to the potential for contamination by perspiration and, where applicable, gloves should be worn. Various types of tweezers are available to cope with small particulate matter, and a moistened fine hair brush will recover paint particles. It is essential that each item of collection equipment is cleaned between individual collections. Swabbing
Dry swabs can be employed to collect minute particles. The fibrous nature of the swab end can be effectively used to collect particulate matter. The material can then be separated, in the laboratory, from the swab on to microscope slides for further microscopic examination. Swabs moistened with distilled or injection water can be used to collect body fluids. Forensic biologists used to prefer body fluids to be collected using cotton threads or small pieces of cotton material. The reason for this is related to the dilution and dispersion of the sample. For early electrophoretic techniques localized concentration was important and therefore the thread-type swabbing method was preferred. Now with DNA polymerase chain reaction (PCR) amplification, the dispersion and dilution of body fluids found on a moistened swab no longer present a problem. Tapelifting
Tapelifting is a reliable method of collecting trace microscopic material from a variety of surfaces: in particular, garments and motor vehicle seats. Transparent adhesive tape no more that 7.5 cm in length is applied to the surface of the object. At the completion of the application the tape is placed over a clean piece
of glass or rigid plastic and then placed into a clean labeled plastic bag. Garments and other larger objects should be examined in segments; for example, the front and rear of a shirt as two discrete areas. The tape should only be used while the adhesive qualities remain. Too much material should not be placed on one tape. The collection of material in this manner facilitates the examination of trace evidence using a macroscope and, in particular, assists in sorting material of interest from a myriad of other insignificant material. When using adhesive tape from a dispenser, the first 5 cm should be discarded to prevent contamination. The method of tapelifting is used more widely in the forensic science laboratory, although it does have its uses in the field. Sweeping
This method is particularly useful in collecting material from a variety of areas, including inaccessible sites or those where there is a mass of material. Sweeping is also a useful collection technique for the examination of motor vehicles where large amounts of debris can be present on the floor surfaces, in boots or in engine compartments. It is essential that the brush is clean and that separate brushes are used whenever contamination or cross-transfer is a consideration; for example, examining a scene and a suspect's vehicle. New paint brushes approximately 25 mm wide with nonpainted handles, along with new pans from dustpan and broom sets, should be used on each occasion where sweeping is employed. Vacuuming
The collection of microscopic material, from garments, motor vehicles and other large objects, by vacuuming is another valuable means of collecting
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trace material. However, the circumstances in which it should be employed need to be considered carefully, as the vacuumings collected are difficult to handle, involving the expenditure of a great deal of time in searching them in the laboratory. Furthermore, vacuuming can be too effective, in that it can lead to the collection of a great deal of `ancient history'. This method requires a specialized nozzle for the vacuum cleaner. Nozzles are custom made from stainless steel. Plastic demonstration traps have also been employed in the field. Material is collected by suction on to a clean filter paper (stainless steel) or cotton material (plastic), which rests on a perforated plate located in the central compartment. Some situations may warrant the use of an ordinary vacuum cleaner with a clean bag for collecting trace material; however, this is a last resort as you will add material to the collection sample from traces which remain in the vacuum hose. When using the stainless steel and plastic traps, care must be taken to ensure that the nozzle, trap and suction end of the traps are cleaned before use, or when vacuuming separate articles or particular localized regions of an object, vehicle or scene. The nozzle should be washed in warm soapy water, rinsed with clean water and dried. Bottle brushes are ideal for cleaning nozzle pipes. When in the field away from the ability to clean the nozzle it must be brushed clean between each use. A blank/control vacuuming should be run before the actual sampling run, with a clean filter paper in place. This is then removed and bagged separately for later examination. Each sample run must also have a clean piece of filter paper, likewise a new bag as a control and new bag for the sample run if a trap nozzle is not available. Once set up ready for a sample run, the nozzle is applied to the surface; for example, with a garment in a series of strokes. Each area of the garment will be a discrete searching area in its own right; for example, pockets, back and front of garment. When not in use the nozzle should be cleaned and stored in a sealed plastic bag.
Preservation Items must be preserved so that they remain, as far as possible, in their original state and may be produced in court in the condition in which they were found. In some cases it is not possible to retain the exhibit intact; for example, in analytical procedures the item may have to be altered or it may be totally consumed in the procedure. The crime scene investigator should take all neces-
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sary steps to protect items collected from the following: Loss Small items such as hairs, fibers and paint flakes may be lost from packages that are not properly sealed. Envelopes on their own are unsuitable for small samples as the particulate matter may be lost through corners of the envelope. Volatile liquids from fire scenes may evaporate if the containers are not airtight and impermeable. Deterioration or damage Biological material such as wet blood or seminal stains may deteriorate rapidly. Valuable shoe impressions and blood stains in outdoor scenes must be protected and collected before wind and rain destroys them. Contamination Items which are not properly packaged may become contaminated by the introduction of foreign matter into the packaging. Tampering Items should be packaged securely and should not be left unattended. The crime scene investigator should guard against innocent tampering as well as that intended to destroy potential evidence; for example, a firearm left unattended with a fired cartridge case in the breech may arrive at the forensic science laboratory with several impressions on the firing pin if the firearm is not packaged appropriately and secured.
Sealing Containers The sealing of containers is necessary to keep items from being lost, contaminated or tampered with. The container should be sealed with sealing tape and then with evidence tape. The evidence tape should be signed by the crime scene investigator/collector.
Chain of Custody The chain of custody refers to the documentation of possession of items from their recovery collection through examinations to their tendering in court as potential items of evidence. This allows interested parties to trace who has had custody of the item at a given time, as well as being able to account for where the item has been while it has been in an individual's or organization's custody. Proximal containers, and, if applicable, items should be labeled with a movement record of the container/item, and the case file and/or the exhibit movement log should also record the movement of the item.
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Hazard Labeling It will be necessary to mark containers with appropriate hazard labels. Those that contain items which are stained with body fluids should be marked with a biological hazard label, and those that contain items that have been treated with chemicals to enhance fingerprints should be marked with a chemical hazard label. This should go some way in encouraging court staff to resist the temptation to open all packages and dispense with containers before the item is tendered as an exhibit in court.
Summary This article has discussed packaging material and how to deal with infested material, covering the techniques employed and the sequence of collecting items. Chain of custody has been covered, as has the use of appropriate labeling and sealing. Appendix 1 outlines the collection of specific items normally encountered in crime scene investigation, pointing out the most appropriate packaging and collection technique and the significance of each specific item. See also: Crime-scene Investigation and Examination: Recording; Collection and Chain of Evidence; Recovery of Human Remains; Preservation; Contamination; Major Incident Scene Management.
Further Reading Goddard KW (1977) Crime Scene Investigation. Reston, VA: Reston. Fisher BAJ (1993) Techniques of Crime Scene Investigation, 5th edn. Boca Raton, FL: CRC Press. Forensic Science Service (1999) The Scenes of Crime Handbook. Birmingham, UK: Forensic Science Service. Horswell J (1993) Crime scene investigation. In: Freckelton I and Selby H (eds) Expert Evidence, pp. 8-7301±87611. North Ryde, NSW: Law Book Co. Kirk P (1974) Crime Investigation, 2nd edn. Chichester: Wiley. Svensson A and Wendel O (1974) Techniques of Crime Scene Investigation, 2nd edn. New York: Elsevier.
Appendix 1 Collection and Packaging The following is offered as a guide to the collection and packaging of commonly encountered items of physical evidence. Ammunition
This includes projectiles, live and expended cartridges, shot and wads. 1. Wrap with tissue paper, or in the case of distorted projectile fragments in a small plastic bag, and
place each item in a separate plastic or cardboard container. Never mark ammunition ± label the proximal container instead. 2. Wash projectiles and air dry if removed during autopsy. Packaging: Item placed in a plastic bag then inserted into a rigid plastic or cardboard container. Do not use cotton wool or tissue paper for fragmented and distorted projectiles. Significance: Determine type of ammunition and its origin. Bite marks
On skin 1. Photograph with colour and black and white ultraviolet film at 908 using a scale rule and gray card. 2. Wipe the area with a piece of cotton, moistened with distilled water, air dry, then place in a plastic tube. 3. Cast mark, if possible; place cast in small rigid plastic container. Significance In consultation with an odontologist, comparison of bite mark with any suspect's teeth and possible DNA analysis. On perishable items 1. Photograph. 2. Cast mark. Packaging
Place cast into a rigid plastic container.
Significance In consultation with an odontologist, comparison of bite mark with any suspect's teeth. Suspect 1. Photograph teeth (five positions). 2. Obtain saliva using sterile cotton gauze, air dry and package. 3. Cast teeth of suspect; casts usually remain with the odontologist. Packaging Place (2) in small rigid plastic container. Place (3) in small cardboard box. Significance (1) and (3) are for use by the consulting odontologist for comparison work with bite marks and suspect's teeth; (2) for possible DNA analysis. Blood
On absorbent material 1. Cut material, air dry and package separately. 2. Cut out a control sample. Packaging
Large blood-stained items should be
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packaged in paper; small samples that have been dried should be placed in plastic phials and labeled. Significance Blood grouping and/or DNA. Comparison of results with reference samples. On nonabsorbent material Wet For large volumes spoon or suck up with a disposable pipette liquid blood and package. For small volumes rub a small piece of cotton through the stain. Dry For large volumes using a scalpel scrape into a small rigid plastic container. For small volumes rub a piece of previously moistened (distilled water) cotton through the stain and transfer the stain from the substrate to the cotton. In both instances Controls from unstained area by moistening a piece of cotton and rubbing unstained area. Packaging
Plastic or glass phials.
Significance Blood grouping and/or DNA. Comparison of results with reference samples. Whole blood
1. Obtained by doctor or nursing staff. Three samples: one straight sample and one with anticoagulant. 2. One with preservative. Packaging For (1) glass or plastic phials. Anticoagulant: EDTA seeded pink top. For (2), placed in a preservative: sodium oxalate seeded brown top plastic phial. Significance For (1), reference samples for blood grouping and/or DNA. Comparison of results with crime scene stains. Bloodstain pattern interpretation
1. Use a large format camera, 6 6 6 cm minimum. 2. Photograph scene with black and white and color film. 3. Take overview photographs of stains at 908 from each subject. 4. Take close up views including measuring tape. 5. Take blood sample/s. Packaging
As above.
Significance Aid in the reconstruction of events and identify the donor of the blood stains.
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Cigarette butts
1. Collect with plastic tweezers, air dry and package. 2. Examine for trace evidence: lipstick and fingerprints. Packaging Plastic or glass phials. Package each butt separately. Significance Identify cigarettes: more than one person smoking, DNA saliva residue, fingerprints and lipstick. Clothing
1. Photograph, note and describe. 2. Remove clothing from suspects over clean white paper, air dry and package. 3. Remove any obvious trace material and package separately. Packaging Paper bags. Place each item separately in a paper bag. Significance Comparison with any trace material or blood stains with reference whole blood for proof of contact. Documents
1. Wearing white cotton gloves, collect with tweezers and package. Packaging Place in a prelabeled plastic document sheet or envelope containing a piece of cardboard. Significance Determine origin, indented writing, fingerprints, obliterations or additions, or as material for comparison of handwriting in an attempt to identify the writer. Fibers
1. Collect fibers with tweezers or submit whole item containing fibers. 2. Using the tapelifting collection technique, tape the area of interest using clear transparent adhesive tape and place tape, adhesive side down, on a clear plastic sheet. Packaging Small plastic phial for loose fibers and plastic bags for plastic sheets. Significance
Identify possible source.
Fire debris
1. Collect debris from suspect area. Cut up large pieces of debris and package. 2. Collect control samples for different areas and package.
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Packaging Clean new metal paint cans, nylon bags or PVDC (polyvinylidene chloride) bags. Significance Determine the presence of and type of accelerant and distribution. Firearms discharge residue
2. 3. 4. 5.
Collect fragile fragments first. Wrap each separately to protect edges. Place fragments in suitable container. Collect all pieces if possible.
Packaging Plastic phial for small pieces for analysis; large cardboard boxes for larger pieces.
On hands 1. Photograph any visible evidence. 2. Collect from the web of the hand using adhesive SEM stubs. 3. Take control samples.
Significance Small pieces as control samples for refractive index measurement; identify source by mechanical fit and direction of breaking with larger pieces.
Packaging tion kit.
On clothing
SEM firearm discharge residue collec-
Significance Determine if a firearm has been discharged by the person being tested. On clothing 1. Photograph visible evidence and package. Packaging
Paper bag.
Significance Determine if a firearm has been discharged by the person who owns the clothes. Bullet hole in clothing 1. Photograph with color and black and white (infrared) film. 2. Protect the bullet hole by pinning paper over it. 3. Place cardboard behind area to prevent bending. Do not bend clothing at the bullet hole if it can be avoided. Packaging Significance
Paper bags. Determine distance from target.
Bullet hole in dead skin 1. Photograph with color and black and white (infrared) film. 2. Cut beyond the blackened area. surrounding the bullet hole and identify the `12 o'clock position' with a suture. Packaging
Glass jar and 10% formalin.
1. Collect fragile fragments first. 2. Collect clothing and package separately. Packaging
Plastic phial and paper bags.
Significance Identify possible source by physical and/or chemical analysis. Hairs
On moveable objects 1. Collect and protect the complete item. On fixed objects 1. Using a pair of plastic tweezers collect fibers and package. Control samples Head Pluck 30±40 hairs from various areas. Pubic
Pluck 20±30 hairs.
Others Pluck 10±20 hairs from area of interest. Combed and plucked hairs are packaged separately. Packaging Folded paper inserted into an envelope or plastic bag. Significance Determine color, sex and race of person, areas of body, plucked or shed, human or animal. Insects: flies
There are four stages in the life cycle of flies: eggs, maggots, pupae and adults (flies).
At scene in general area
1. Collect 60±80 individuals from each position, on, under and approximately 90±150 cm from the decomposing body. 2. Collect from hidden areas, beneath leaves and floorboards.
1. Photograph both sides of glass before removing it from the frame.
Note Pupae may be found in the form of brown capsules under the body or in soil under the body.
Significance
Firing distance and angle.
Glass
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Packaging Glass container. Place specimens in 70% V/V ethyl alcohol in distilled water.
Packaging Plain glass or plastic tube.
Significance
Significance Reference sample for comparison with scene and other unknown stains.
Estimation of time of death.
Maggots
1. Collect two samples, each containing 60±80 individuals. 2. Package one sample with some flesh. 3. Package second sample in alcohol or formalin.
Blood for serology 1. Obtain clean arterial blood (10 ml).
Packaging
Significance Reference sample for comparison with scene and other unknown stains.
Significance
Glass bottles. Estimation of time of death.
Paint
On tools or vehicles 1. If possible collect the item (tool or vehicle) containing the evidence. 2. Collect paint chips separately. 3. Care should be taken not to fragment paint chips. 4. Take reference samples of each color, ensuring they are scraped down to the base color. Packaging Folded paper inserted into an envelope or plastic bag or rigid plastic container. Significance Determine possible source: color, model, type of vehicle. Identify the vehicle when it comes to notice. On clothing 1. Collect fragile evidence first. 2. Collect clothing and package individually. Packaging Folded paper in an envelope or plastic bag and rigid plastic container. Significance Determine possible source: color, model, type of vehicle. Identify the vehicle when it comes to notice. Postmortem samples
Alcohol 1. Obtain clean arterial blood (10 ml). 2. Obtain urine (10 ml). 3. Obtain vitreous humor (10 ml). Packaging Plastic tube containing a preservative (oxalate or fluoride). Significance
Indicates state of intoxication.
Blood for DNA 1. Obtain clean arterial blood (10 ml).
Packaging
Pink top plastic tube containing EDTA.
Drugs 1. Obtain clean arterial blood (10 ml). 2. Obtain urine (10 ml). Packaging Plain glass or plastic tubes without anticoagulant or preservative. Significance Indicate if under the influence of drugs or is a drug abuser. Toxicology 1. Obtain clean arterial blood (10 ml). 2. Obtain a portion of liver (100 g). 3. Obtain all the stomach contents. 4. Obtain vitreous humor (10 ml). Packaging Significance
Plastic containers. Poisons determination.
Diatoms 1. Obtain a portion of femur (15 cm). Packaging
Glass containing alcohol.
Significance To establish location of drowning: fresh water or salt water. Safe insulation
From suspect's clothing 1. Collect clothing and package separately. Packaging
Paper bags.
Significance Comparison of any trace material found with a reference sample of safe insulation. From safe 1. Collect reference sample of safe insulation from the safe. Packaging
Rigid plastic container.
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Significance For comparison with any trace material found on suspect or his or her environment and therefore to link suspect with the scene. Saliva
1. Collect saliva (ensure it is saliva and not mucus) on clean white gauze (wear gloves). 2. Air dry and package. Packaging Significance substances.
Rigid plastic container. DNA and determination of ABO group
Seminal stains
1. Photograph stains and their distribution. 2. Collect items exhibiting stains (wear gloves). 3. Air dry and package. Packaging
Paper bags.
Significance Identification of donor by DNA and/or blood grouping. Soil
1. Collect sample from suspect vehicle or footwear. 2. Collect clothing from suspect. 3. Collect several separate samples from scene and surrounding area as reference samples (50 g). Packaging Rigid plastic containers for the soil and paper bags for the clothing. Significance Geographical origin of samples, possible link between suspect and scene. Tools
1. Photograph where located. 2. Protect working ends. Packaging
Plastic bags.
Significance Location of paint on cutting edge which may match paint at the scene and to link the tool to a particular toolmark. Toolmark
1. Photograph (overview, midrange and close-up with scale). 2. Make a cast. 3. Recover complete item for further examination if it is portable. Packaging Significance
Rigid plastic container or plastic bag. Link toolmark to a particular tool.
Vegetation
1. Photograph various types of vegetation. 2. Collect samples consisting of complete plants and roots. Packaging Paper bags with cardboard stiffening to prevent damage. Significance Identify species and compare with trace material found on suspect or his or her environment. Wires
1. Photograph site. 2. Protect ends of wire. 3. Label ends cut by crime scene investigator. Packaging
Plastic bags.
Significance Identify tool type and compare with tools submitted for examination for possible identification of the tool. Notes 1. Potential evidence should be recovered and submitted to the laboratory as soon as possible and examination of individual items at the scene should be kept to a minimum. 2. The above are general guidelines. Different jurisdictions may advocate some variation on these procedures.
Preservation H B Baldwin, Forensic Enterprises Inc., Orland Park, IL, USA C Puskarich May, Criminal Justice Institute, Little Rock, AR, USA Copyright # 2000 Academic Press doi:10.1006/rwfs.2000.0453
Introduction For the purpose of this article, `preservation' in the realm of law enforcement will involve two areas: preservation of the crime scene and physical evidence preservation. The primary purpose of both forms of preservation is to limit or eliminate the potential for contamination or destruction. In doing so, the crime scene/physical evidence can be appropriately processed and documented. Securing and protecting the crime scene will lead to a more accurate reconstruction of the crime and have an impact on its solvability.
Packaging J Horswell, Australian Federal Police, Canberra, Australia Copyright # 2000 Academic Press doi:10.1006/rwfs.2000.0452
Background The ideal method of collecting and subsequent packing of items for transport to the forensic science laboratory will vary considerably depending on the nature of the item concerned. Likewise the material from which a package is fabricated will also vary considerably.
Infested Material In some instances material recovered from crime scenes or mortuaries for return to the forensic science laboratory, or for long-term storage as property, may be infested with pests, such as fleas, lice, maggots or coffin beetles. Care must be taken when examining this material by wearing protective clothing and gloves. If possible, always use a large open search bench. If insect infestation is present within the item there are at least two methods available for killing them: . Place the material and container in a large plastic bag and seal it. Place the bag into a deep freeze until the insects are dead. . Add a few drops of ethyl formate to the plastic bag containing the item and its container. Seal the bag and leave for approximately 1 h or until the insects are dead. Where blood or semen stains are present, samples from stains must be collected prior to freezing. Consideration should also be given to entomological aspects of the case: both live and dead insect specimens may be required for examination.
Collection of Items Paper as a Packaging Medium Generally, the use of paper in the form of bags of various sizes is recommended. Paper bags are fabricated in various sizes and should be readily available. If using envelopes, A4 white bond paper should be employed in the first instance for small items such as hairs, fibers, glass or paint. Place the item onto previously folded paper and then place this in an envelope. This will prevent the loss of items from envelope corners, and the use of folded paper will simplify the subsequent examination under a macroscope. The placement of clothing and biological material in paper allows the item to breath; placement in a plastic bag may result in bacterial action and encourage the growth of mold. All items should be air dried prior to packaging in paper. Extensively blood-stained or semen-stained items recovered from crime scenes should be first placed into paper and then protected by a plastic bag; however, the item must be removed from packaging on arrival at the forensic science laboratory and air dried. Items wet with volatile substances should be placed in nylon bags or new, clean, paint cans. Normal polyethylene bags are not suitable for the retention of volatiles.
Quantity It is better to collect excess material than to have an examination fail because there is insufficient material for analysis. Where difficulty may be encountered in collecting minute traces of substances, specialist collection techniques should be employed. If, however, traces of evidence are on small items and there is a chance of loss, the trace subsample should be recovered and placed into a separate package. If the trace is a stain then the stain should remain on the item for assessment in the forensic science laboratory. This is particularly relevant where the item as a whole is vitally relevant; for example, a blood-stained knife. Controls In many cases involving stained material, for example fire debris, it is necessary to submit unstained material for analysis to determine if the material itself interferes with the analytical procedures. Reference material In any comparison of the constituents of two substances, sufficient reference sample material should be provided. For example, if dust on clothing is suspected of being ballast from a particular safe, a sufficient amount should be collected, packaged and submitted together with the items of clothing in order that a satisfactory comparison may be performed. The reference sample should be repre-
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sentative of the source from which the test sample originated. For example, it is useless attempting to compare a body hair found at the scene with a head hair from the suspect. Similarly, the comparison of soil from a shoe with soil from the scene may be unsuccessful if the sources of the two samples are separated by only a few meters. Labeling
The purpose of a label is twofold: . to identify the nature and source of the item; . to establish a chain of custody. Ideally, a label should have the following information recorded on it: . nature of contents; . source (where found or from who recovered); . date and time; . signature and printed surname of collector; . sequential number; . unique case identifying number. Additionally, room should be available on the label to record the movement of the item. The label should be completed at the time of collection or receipt of the item. If an item is collected from a person, use that person's name; for example, `Trousers from John Smith'. Do not mark the item with the word `Suspect', as this may lead to the exhibit being excluded from a trial. Some courts are of the view that to mark items in this way is `unnecessary' and `objectionable' because whenever such an item is mentioned in evidence during the trial the jury are being told that the accused has been a suspect. This perhaps gives the impression that he or she was a suspect early in the investigation, which need not necessarily be the case. The jury may also wrongly hold the view that there may be more to know about the accused, which could be prejudicial. Obviously the word `offender' should never be used at this is a presumption of guilt. The sequential number used should relate to the collectors item list and could be JH1, JH2, JH3, etc. When making a subsequent examination of the items collected, any material removed should be given a number that relates to the original item. For example a pair of trousers is marked JH1 and hair is recovered from the trousers. This item should be marked JH1.1. In this way each subsample can be traced easily back to the original source item. Where the item is something substantial, for example a knife or clothing, then the exhibit itself should be marked as well as the container. It may be appropriate to tie a label with a piece of string to the item. If this is done then there can be no doubt about later identifying the item in the witness box should it be
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separated from its container. If using plastic pots or vials, ensure that there is a corresponding mark on both the lid and the container to avoid any mixing up of the containers. The sequential number and unique case number are normally used for this purpose. Collection
The proper collection of items and trace material is essential in obtaining the greatest evidential value from an examination. Special clothing should be worn during all scene and laboratory examinations. Scene suits, white cotton overalls or laboratory coats should always be worn as white cotton has the least evidential value as a fiber and is therefore suitable in preventing contamination of scenes or clothing with fibers from the examiner's clothing. There is also an occupational health and safety dimension to the use of appropriate clothing. Collection case
Collection cases must be kept clean, with equipment stored in an orderly manner. The principal collection items and their uses are listed in Table 1.
Collection Techniques A variety of techniques have been developed for the collection of trace material and other potential evidential material. Each technique is designed to prevent damage to, and contamination of, the material. The main collection techniques can be described as: . . . . .
handpicking; tape lifting; swabbing; sweeping; vacuuming.
Handpicking
Whenever examining the crime scene, garments, bodies or other articles, the initial emphasis should be directed toward the collection of gross and macroscopic items that can be recovered by hand or by the use of tweezers. Items large enough to see with the naked eye should be collected by handpicking. Material such as hairs, large paint and glass fragments and pieces of vegetation should be collected before the application of other collection techniques, such as tapelifting, sweeping and vacuuming. Handpicking has the advantage of establishing the position of the material on the item and requires no further time in searching, whereas tapelifts, sweepings and vacuumings have to be further searched to
434 CRIME-SCENE INVESTIGATION AND EXAMINATION/Packaging Table 1 Principal items of collection equipment and their uses Item
Collection use
Scalpel Probe Brush Swab Paint brush Spatula Tweezers (metal) Tweezers (plastic)
Paint smears, visible fibers, vegetation and dried blood Paint, fibers, residues, oils, greases; manipulation of microscopic particles Trace particles: paint, metals, vegetation, glass Small particles, which will be caught in the coarse fibers of the swab To sweep localized and constricted areas Soil samples, whole or partly congealed blood; mixing of casting compound Trace material, such as fibers, hair and vegetation Items that may be damaged if metal tweezers are used; recovery of bullets and fragments during postmortem examinations and for use when recovering blood stains using small pieces of moistened white cotton. Employed where cleaning is not possible and a number are required. Each tweezer is inexpensive therefore can be destroyed after each use Dried blood linen stains once moistened with distilled water Particles of iron and steel, after covering the magnet with plastic
Cotton Magnet
isolate small particulate matter of interest. When collecting items by hand, consideration should be given to the potential for contamination by perspiration and, where applicable, gloves should be worn. Various types of tweezers are available to cope with small particulate matter, and a moistened fine hair brush will recover paint particles. It is essential that each item of collection equipment is cleaned between individual collections. Swabbing
Dry swabs can be employed to collect minute particles. The fibrous nature of the swab end can be effectively used to collect particulate matter. The material can then be separated, in the laboratory, from the swab on to microscope slides for further microscopic examination. Swabs moistened with distilled or injection water can be used to collect body fluids. Forensic biologists used to prefer body fluids to be collected using cotton threads or small pieces of cotton material. The reason for this is related to the dilution and dispersion of the sample. For early electrophoretic techniques localized concentration was important and therefore the thread-type swabbing method was preferred. Now with DNA polymerase chain reaction (PCR) amplification, the dispersion and dilution of body fluids found on a moistened swab no longer present a problem. Tapelifting
Tapelifting is a reliable method of collecting trace microscopic material from a variety of surfaces: in particular, garments and motor vehicle seats. Transparent adhesive tape no more that 7.5 cm in length is applied to the surface of the object. At the completion of the application the tape is placed over a clean piece
of glass or rigid plastic and then placed into a clean labeled plastic bag. Garments and other larger objects should be examined in segments; for example, the front and rear of a shirt as two discrete areas. The tape should only be used while the adhesive qualities remain. Too much material should not be placed on one tape. The collection of material in this manner facilitates the examination of trace evidence using a macroscope and, in particular, assists in sorting material of interest from a myriad of other insignificant material. When using adhesive tape from a dispenser, the first 5 cm should be discarded to prevent contamination. The method of tapelifting is used more widely in the forensic science laboratory, although it does have its uses in the field. Sweeping
This method is particularly useful in collecting material from a variety of areas, including inaccessible sites or those where there is a mass of material. Sweeping is also a useful collection technique for the examination of motor vehicles where large amounts of debris can be present on the floor surfaces, in boots or in engine compartments. It is essential that the brush is clean and that separate brushes are used whenever contamination or cross-transfer is a consideration; for example, examining a scene and a suspect's vehicle. New paint brushes approximately 25 mm wide with nonpainted handles, along with new pans from dustpan and broom sets, should be used on each occasion where sweeping is employed. Vacuuming
The collection of microscopic material, from garments, motor vehicles and other large objects, by vacuuming is another valuable means of collecting
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trace material. However, the circumstances in which it should be employed need to be considered carefully, as the vacuumings collected are difficult to handle, involving the expenditure of a great deal of time in searching them in the laboratory. Furthermore, vacuuming can be too effective, in that it can lead to the collection of a great deal of `ancient history'. This method requires a specialized nozzle for the vacuum cleaner. Nozzles are custom made from stainless steel. Plastic demonstration traps have also been employed in the field. Material is collected by suction on to a clean filter paper (stainless steel) or cotton material (plastic), which rests on a perforated plate located in the central compartment. Some situations may warrant the use of an ordinary vacuum cleaner with a clean bag for collecting trace material; however, this is a last resort as you will add material to the collection sample from traces which remain in the vacuum hose. When using the stainless steel and plastic traps, care must be taken to ensure that the nozzle, trap and suction end of the traps are cleaned before use, or when vacuuming separate articles or particular localized regions of an object, vehicle or scene. The nozzle should be washed in warm soapy water, rinsed with clean water and dried. Bottle brushes are ideal for cleaning nozzle pipes. When in the field away from the ability to clean the nozzle it must be brushed clean between each use. A blank/control vacuuming should be run before the actual sampling run, with a clean filter paper in place. This is then removed and bagged separately for later examination. Each sample run must also have a clean piece of filter paper, likewise a new bag as a control and new bag for the sample run if a trap nozzle is not available. Once set up ready for a sample run, the nozzle is applied to the surface; for example, with a garment in a series of strokes. Each area of the garment will be a discrete searching area in its own right; for example, pockets, back and front of garment. When not in use the nozzle should be cleaned and stored in a sealed plastic bag.
Preservation Items must be preserved so that they remain, as far as possible, in their original state and may be produced in court in the condition in which they were found. In some cases it is not possible to retain the exhibit intact; for example, in analytical procedures the item may have to be altered or it may be totally consumed in the procedure. The crime scene investigator should take all neces-
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sary steps to protect items collected from the following: Loss Small items such as hairs, fibers and paint flakes may be lost from packages that are not properly sealed. Envelopes on their own are unsuitable for small samples as the particulate matter may be lost through corners of the envelope. Volatile liquids from fire scenes may evaporate if the containers are not airtight and impermeable. Deterioration or damage Biological material such as wet blood or seminal stains may deteriorate rapidly. Valuable shoe impressions and blood stains in outdoor scenes must be protected and collected before wind and rain destroys them. Contamination Items which are not properly packaged may become contaminated by the introduction of foreign matter into the packaging. Tampering Items should be packaged securely and should not be left unattended. The crime scene investigator should guard against innocent tampering as well as that intended to destroy potential evidence; for example, a firearm left unattended with a fired cartridge case in the breech may arrive at the forensic science laboratory with several impressions on the firing pin if the firearm is not packaged appropriately and secured.
Sealing Containers The sealing of containers is necessary to keep items from being lost, contaminated or tampered with. The container should be sealed with sealing tape and then with evidence tape. The evidence tape should be signed by the crime scene investigator/collector.
Chain of Custody The chain of custody refers to the documentation of possession of items from their recovery collection through examinations to their tendering in court as potential items of evidence. This allows interested parties to trace who has had custody of the item at a given time, as well as being able to account for where the item has been while it has been in an individual's or organization's custody. Proximal containers, and, if applicable, items should be labeled with a movement record of the container/item, and the case file and/or the exhibit movement log should also record the movement of the item.
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Hazard Labeling It will be necessary to mark containers with appropriate hazard labels. Those that contain items which are stained with body fluids should be marked with a biological hazard label, and those that contain items that have been treated with chemicals to enhance fingerprints should be marked with a chemical hazard label. This should go some way in encouraging court staff to resist the temptation to open all packages and dispense with containers before the item is tendered as an exhibit in court.
Summary This article has discussed packaging material and how to deal with infested material, covering the techniques employed and the sequence of collecting items. Chain of custody has been covered, as has the use of appropriate labeling and sealing. Appendix 1 outlines the collection of specific items normally encountered in crime scene investigation, pointing out the most appropriate packaging and collection technique and the significance of each specific item. See also: Crime-scene Investigation and Examination: Recording; Collection and Chain of Evidence; Recovery of Human Remains; Preservation; Contamination; Major Incident Scene Management.
Further Reading Goddard KW (1977) Crime Scene Investigation. Reston, VA: Reston. Fisher BAJ (1993) Techniques of Crime Scene Investigation, 5th edn. Boca Raton, FL: CRC Press. Forensic Science Service (1999) The Scenes of Crime Handbook. Birmingham, UK: Forensic Science Service. Horswell J (1993) Crime scene investigation. In: Freckelton I and Selby H (eds) Expert Evidence, pp. 8-7301±87611. North Ryde, NSW: Law Book Co. Kirk P (1974) Crime Investigation, 2nd edn. Chichester: Wiley. Svensson A and Wendel O (1974) Techniques of Crime Scene Investigation, 2nd edn. New York: Elsevier.
Appendix 1 Collection and Packaging The following is offered as a guide to the collection and packaging of commonly encountered items of physical evidence. Ammunition
This includes projectiles, live and expended cartridges, shot and wads. 1. Wrap with tissue paper, or in the case of distorted projectile fragments in a small plastic bag, and
place each item in a separate plastic or cardboard container. Never mark ammunition ± label the proximal container instead. 2. Wash projectiles and air dry if removed during autopsy. Packaging: Item placed in a plastic bag then inserted into a rigid plastic or cardboard container. Do not use cotton wool or tissue paper for fragmented and distorted projectiles. Significance: Determine type of ammunition and its origin. Bite marks
On skin 1. Photograph with colour and black and white ultraviolet film at 908 using a scale rule and gray card. 2. Wipe the area with a piece of cotton, moistened with distilled water, air dry, then place in a plastic tube. 3. Cast mark, if possible; place cast in small rigid plastic container. Significance In consultation with an odontologist, comparison of bite mark with any suspect's teeth and possible DNA analysis. On perishable items 1. Photograph. 2. Cast mark. Packaging
Place cast into a rigid plastic container.
Significance In consultation with an odontologist, comparison of bite mark with any suspect's teeth. Suspect 1. Photograph teeth (five positions). 2. Obtain saliva using sterile cotton gauze, air dry and package. 3. Cast teeth of suspect; casts usually remain with the odontologist. Packaging Place (2) in small rigid plastic container. Place (3) in small cardboard box. Significance (1) and (3) are for use by the consulting odontologist for comparison work with bite marks and suspect's teeth; (2) for possible DNA analysis. Blood
On absorbent material 1. Cut material, air dry and package separately. 2. Cut out a control sample. Packaging
Large blood-stained items should be
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packaged in paper; small samples that have been dried should be placed in plastic phials and labeled. Significance Blood grouping and/or DNA. Comparison of results with reference samples. On nonabsorbent material Wet For large volumes spoon or suck up with a disposable pipette liquid blood and package. For small volumes rub a small piece of cotton through the stain. Dry For large volumes using a scalpel scrape into a small rigid plastic container. For small volumes rub a piece of previously moistened (distilled water) cotton through the stain and transfer the stain from the substrate to the cotton. In both instances Controls from unstained area by moistening a piece of cotton and rubbing unstained area. Packaging
Plastic or glass phials.
Significance Blood grouping and/or DNA. Comparison of results with reference samples. Whole blood
1. Obtained by doctor or nursing staff. Three samples: one straight sample and one with anticoagulant. 2. One with preservative. Packaging For (1) glass or plastic phials. Anticoagulant: EDTA seeded pink top. For (2), placed in a preservative: sodium oxalate seeded brown top plastic phial. Significance For (1), reference samples for blood grouping and/or DNA. Comparison of results with crime scene stains. Bloodstain pattern interpretation
1. Use a large format camera, 6 6 6 cm minimum. 2. Photograph scene with black and white and color film. 3. Take overview photographs of stains at 908 from each subject. 4. Take close up views including measuring tape. 5. Take blood sample/s. Packaging
As above.
Significance Aid in the reconstruction of events and identify the donor of the blood stains.
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Cigarette butts
1. Collect with plastic tweezers, air dry and package. 2. Examine for trace evidence: lipstick and fingerprints. Packaging Plastic or glass phials. Package each butt separately. Significance Identify cigarettes: more than one person smoking, DNA saliva residue, fingerprints and lipstick. Clothing
1. Photograph, note and describe. 2. Remove clothing from suspects over clean white paper, air dry and package. 3. Remove any obvious trace material and package separately. Packaging Paper bags. Place each item separately in a paper bag. Significance Comparison with any trace material or blood stains with reference whole blood for proof of contact. Documents
1. Wearing white cotton gloves, collect with tweezers and package. Packaging Place in a prelabeled plastic document sheet or envelope containing a piece of cardboard. Significance Determine origin, indented writing, fingerprints, obliterations or additions, or as material for comparison of handwriting in an attempt to identify the writer. Fibers
1. Collect fibers with tweezers or submit whole item containing fibers. 2. Using the tapelifting collection technique, tape the area of interest using clear transparent adhesive tape and place tape, adhesive side down, on a clear plastic sheet. Packaging Small plastic phial for loose fibers and plastic bags for plastic sheets. Significance
Identify possible source.
Fire debris
1. Collect debris from suspect area. Cut up large pieces of debris and package. 2. Collect control samples for different areas and package.
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Packaging Clean new metal paint cans, nylon bags or PVDC (polyvinylidene chloride) bags. Significance Determine the presence of and type of accelerant and distribution. Firearms discharge residue
2. 3. 4. 5.
Collect fragile fragments first. Wrap each separately to protect edges. Place fragments in suitable container. Collect all pieces if possible.
Packaging Plastic phial for small pieces for analysis; large cardboard boxes for larger pieces.
On hands 1. Photograph any visible evidence. 2. Collect from the web of the hand using adhesive SEM stubs. 3. Take control samples.
Significance Small pieces as control samples for refractive index measurement; identify source by mechanical fit and direction of breaking with larger pieces.
Packaging tion kit.
On clothing
SEM firearm discharge residue collec-
Significance Determine if a firearm has been discharged by the person being tested. On clothing 1. Photograph visible evidence and package. Packaging
Paper bag.
Significance Determine if a firearm has been discharged by the person who owns the clothes. Bullet hole in clothing 1. Photograph with color and black and white (infrared) film. 2. Protect the bullet hole by pinning paper over it. 3. Place cardboard behind area to prevent bending. Do not bend clothing at the bullet hole if it can be avoided. Packaging Significance
Paper bags. Determine distance from target.
Bullet hole in dead skin 1. Photograph with color and black and white (infrared) film. 2. Cut beyond the blackened area. surrounding the bullet hole and identify the `12 o'clock position' with a suture. Packaging
Glass jar and 10% formalin.
1. Collect fragile fragments first. 2. Collect clothing and package separately. Packaging
Plastic phial and paper bags.
Significance Identify possible source by physical and/or chemical analysis. Hairs
On moveable objects 1. Collect and protect the complete item. On fixed objects 1. Using a pair of plastic tweezers collect fibers and package. Control samples Head Pluck 30±40 hairs from various areas. Pubic
Pluck 20±30 hairs.
Others Pluck 10±20 hairs from area of interest. Combed and plucked hairs are packaged separately. Packaging Folded paper inserted into an envelope or plastic bag. Significance Determine color, sex and race of person, areas of body, plucked or shed, human or animal. Insects: flies
There are four stages in the life cycle of flies: eggs, maggots, pupae and adults (flies).
At scene in general area
1. Collect 60±80 individuals from each position, on, under and approximately 90±150 cm from the decomposing body. 2. Collect from hidden areas, beneath leaves and floorboards.
1. Photograph both sides of glass before removing it from the frame.
Note Pupae may be found in the form of brown capsules under the body or in soil under the body.
Significance
Firing distance and angle.
Glass
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Packaging Glass container. Place specimens in 70% V/V ethyl alcohol in distilled water.
Packaging Plain glass or plastic tube.
Significance
Significance Reference sample for comparison with scene and other unknown stains.
Estimation of time of death.
Maggots
1. Collect two samples, each containing 60±80 individuals. 2. Package one sample with some flesh. 3. Package second sample in alcohol or formalin.
Blood for serology 1. Obtain clean arterial blood (10 ml).
Packaging
Significance Reference sample for comparison with scene and other unknown stains.
Significance
Glass bottles. Estimation of time of death.
Paint
On tools or vehicles 1. If possible collect the item (tool or vehicle) containing the evidence. 2. Collect paint chips separately. 3. Care should be taken not to fragment paint chips. 4. Take reference samples of each color, ensuring they are scraped down to the base color. Packaging Folded paper inserted into an envelope or plastic bag or rigid plastic container. Significance Determine possible source: color, model, type of vehicle. Identify the vehicle when it comes to notice. On clothing 1. Collect fragile evidence first. 2. Collect clothing and package individually. Packaging Folded paper in an envelope or plastic bag and rigid plastic container. Significance Determine possible source: color, model, type of vehicle. Identify the vehicle when it comes to notice. Postmortem samples
Alcohol 1. Obtain clean arterial blood (10 ml). 2. Obtain urine (10 ml). 3. Obtain vitreous humor (10 ml). Packaging Plastic tube containing a preservative (oxalate or fluoride). Significance
Indicates state of intoxication.
Blood for DNA 1. Obtain clean arterial blood (10 ml).
Packaging
Pink top plastic tube containing EDTA.
Drugs 1. Obtain clean arterial blood (10 ml). 2. Obtain urine (10 ml). Packaging Plain glass or plastic tubes without anticoagulant or preservative. Significance Indicate if under the influence of drugs or is a drug abuser. Toxicology 1. Obtain clean arterial blood (10 ml). 2. Obtain a portion of liver (100 g). 3. Obtain all the stomach contents. 4. Obtain vitreous humor (10 ml). Packaging Significance
Plastic containers. Poisons determination.
Diatoms 1. Obtain a portion of femur (15 cm). Packaging
Glass containing alcohol.
Significance To establish location of drowning: fresh water or salt water. Safe insulation
From suspect's clothing 1. Collect clothing and package separately. Packaging
Paper bags.
Significance Comparison of any trace material found with a reference sample of safe insulation. From safe 1. Collect reference sample of safe insulation from the safe. Packaging
Rigid plastic container.
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Significance For comparison with any trace material found on suspect or his or her environment and therefore to link suspect with the scene. Saliva
1. Collect saliva (ensure it is saliva and not mucus) on clean white gauze (wear gloves). 2. Air dry and package. Packaging Significance substances.
Rigid plastic container. DNA and determination of ABO group
Seminal stains
1. Photograph stains and their distribution. 2. Collect items exhibiting stains (wear gloves). 3. Air dry and package. Packaging
Paper bags.
Significance Identification of donor by DNA and/or blood grouping. Soil
1. Collect sample from suspect vehicle or footwear. 2. Collect clothing from suspect. 3. Collect several separate samples from scene and surrounding area as reference samples (50 g). Packaging Rigid plastic containers for the soil and paper bags for the clothing. Significance Geographical origin of samples, possible link between suspect and scene. Tools
1. Photograph where located. 2. Protect working ends. Packaging
Plastic bags.
Significance Location of paint on cutting edge which may match paint at the scene and to link the tool to a particular toolmark. Toolmark
1. Photograph (overview, midrange and close-up with scale). 2. Make a cast. 3. Recover complete item for further examination if it is portable. Packaging Significance
Rigid plastic container or plastic bag. Link toolmark to a particular tool.
Vegetation
1. Photograph various types of vegetation. 2. Collect samples consisting of complete plants and roots. Packaging Paper bags with cardboard stiffening to prevent damage. Significance Identify species and compare with trace material found on suspect or his or her environment. Wires
1. Photograph site. 2. Protect ends of wire. 3. Label ends cut by crime scene investigator. Packaging
Plastic bags.
Significance Identify tool type and compare with tools submitted for examination for possible identification of the tool. Notes 1. Potential evidence should be recovered and submitted to the laboratory as soon as possible and examination of individual items at the scene should be kept to a minimum. 2. The above are general guidelines. Different jurisdictions may advocate some variation on these procedures.
Preservation H B Baldwin, Forensic Enterprises Inc., Orland Park, IL, USA C Puskarich May, Criminal Justice Institute, Little Rock, AR, USA Copyright # 2000 Academic Press doi:10.1006/rwfs.2000.0453
Introduction For the purpose of this article, `preservation' in the realm of law enforcement will involve two areas: preservation of the crime scene and physical evidence preservation. The primary purpose of both forms of preservation is to limit or eliminate the potential for contamination or destruction. In doing so, the crime scene/physical evidence can be appropriately processed and documented. Securing and protecting the crime scene will lead to a more accurate reconstruction of the crime and have an impact on its solvability.