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Fingermark recovery from riot debris: Bricks and stones
Science and Justice 55 (2015) 97–102
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Science and Justice journal homepage: www.elsevier.com/locate/scijus
Fingermark recovery from riot debris: Bricks and stones Lisa Davis ⁎, Ruth Fisher Nottingham Trent University, United Kingdom
a r t i c l e
i n f o
Article history: Received 12 September 2014 Received in revised form 6 January 2015 Accepted 20 January 2015 Keywords: Bricks and stones Casting material Fingermark recovery Fluorescent powder Silver nitrate Superglue
a b s t r a c t During the UK riots in August 2011, large volumes of bricks and stones were used as weapons or projectiles in acts of violence or to gain illegal entry to properties. As a result, it has been emphasised that it is necessary to determine suitable chemical treatment(s) that will enable the development of fingermarks on such items in order to identify those involved. This study has undertaken the task of attempting to develop latent fingermarks on common house bricks, limestone and sandstone using current techniques including ninhydrin and fluorescence. Results produced have shown that, with fluorescent fingerprint powder, silver nitrate and superglue providing the best results, it is now possible to enhance fingermarks that were previously left undeveloped. In addition, Isomark T-1 Rapid Grey High Resolution Forensic Impression Material has proved extremely effective as an alternative method of recovering fingermarks developed with fluorescent fingerprint powder. © 2015 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.
1. Introduction Fingermark evidence has been well established in the criminal justice system for over a century. However, with the raised profile of forensic techniques among the population, and the heightened awareness of criminals, it has become necessary to investigate new, less known opportunities for acquiring evidence [1]. One such opportunity is in the recovery of fingermarks from difficult surfaces, such as bricks and stones. Bricks and stones are common artefacts in non-violent crimes such as burglary and theft from motor vehicles, as they are widely available and are ideal items for breaking glass to gain entry. The artefacts are also used in violent crimes, commonly as projectile weapons, most notably in the pursuit of attacking emergency services. This type of violence in the UK peaked in the civil unrest in August 2011, with rioting breaking out in cities across the country, and attacks on emergency services remain commonplace [2]. Despite their wide use in criminal activities, it has long been the accepted view of law enforcement agencies that these surfaces are unsuitable for fingermark recovery. However, preliminary studies have shown that this may not be the case and that, under certain circumstances, fingermark recovery may be possible [3–5].
⁎ Corresponding author. Tel.: +44 7921183068. E-mail address: [email protected] (L. Davis).
The aim of this study was to find appropriate treatment(s) for the enhancement of latent fingermarks on a range of brick and stone surfaces. This was undertaken in three objectives: - To find suitable chemical treatment(s) for the surfaces of bricks and stones; - To explore the suitability of using effective chemical treatments(s) in sequence; and - To find the chemical treatment(s) that produces optimum results in the enhancement of latent fingermarks on bricks and stones.
2. Materials and methods 2.1. Materials A total of ten participants donated fingermarks for the purpose of development in the study. The participants consisted of two males and eight females, aged between 18 and 40 years of age, who varied in donor strength. The participants were predominantly White British, and included smokers, vegetarians, and those who took regular medication. All participants signed consent forms and were assigned a Donor Identification Number to provide anonymity. A single type of brick was tested, common house brick, retrieved from a domestic garden in North Yorkshire. In addition, sandstone and limestone were also tested and were obtained from a local B&Q store in the form of paving stones. Each experiment was repeated a minimum of three times.
http://dx.doi.org/10.1016/j.scijus.2015.01.006 1355-0306/© 2015 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.
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L. Davis, R. Fisher / Science and Justice 55 (2015) 97–102
2.2. Deposition of fingermarks Each participant was asked to wash their hands a half hour before donation, as recommended by Sears et al. [6], and to avoid touching their face in the intervening period. The participants were subsequently asked to deposit fingermarks by pressing the volar pad area of their finger(s) in the assigned area using a natural amount of pressure (approximately 400 g on a standard balance). All marks were treated within 24 h of deposition unless stated otherwise. 2.3. Post-deposition treatment methods 2.3.1. Examination under fluorescence Using Foster and Freeman Crime-lite®, four wavelength ranges were used to examine each of the surface types—blue (430 – 470 nm), violet (400 – 430 nm), green (500 – 550 nm) and blue–green (460 – 510 nm), with goggles containing orange (GG495), pale yellow (GG455), orange/ red (OG570) and orange (OG550) viewing filters, respectively [7]. Surfaces were examined both pre- and post-treatment, with each surface being searched using the grid method [8], recording any results using Foster and Freeman DCS-3 camera equipment. 2.3.2. Fluorescent fingerprint powders Sirchie Fluorescent Latent Print Powders, in ‘GREENescent’, ‘PINKescent’ and ‘REDescent’, were applied using squirrel hair brushes. A small amount of powder was transferred to a brush, and a little placed at the edge of the square being treated and brushed across the surface. To remove excess powder, and to spread powder on rougher surfaces, a circular motion was used rather than a sweeping motion. After application, the area was examined under fluorescence, with the appropriate goggles, with any results recorded using DCS-3. Initially the three powders were tested on limestone to determine the most effective under fluorescence, as limestone provided the smoothest surface and therefore the most likely to give positive results. Consequently, the most effective was used on sandstone and limestone, whilst all three were used on brick. 2.3.3. Ninhydrin The ninhydrin formulation used was that recommended by the Home Office [9], consisting of 25 g ninhydrin dissolved in absolute ethanol, ethyl acetate and acetic acid and then further diluted with HFE7100 to provide a working solution. The working solution was applied to the surface of each item using a pipette, ensuring that enough was applied so that the whole area was just wet. The surface was allowed to dry, before being transferred to the Weiss Gallenkamp oven, set to ninhydrin process, at a temperature of 80 °C and a relative humidity of 65% [7]. The items were placed on the shelf, with the treated surface perpendicular to the shelf, and left in the oven for 15 min. At the end of the 15 min, the items were removed from the oven, and allowed to cool, before examination under both white and fluorescent light, and any results recorded using DCS-3. 2.3.4. Silver nitrate Two solutions were prepared using the methods described by Trozzi, Schwartz and Hollars [10]. In both of these, 30 g silver nitrate (reagent grade purity ≥ 99%) is dissolved, with stirring, in 1000 mL distilled water or 100 mL distilled water and 1000 mL ethanol, respectively. The first solution was designed for porous surfaces, while the other was designed for hydrophobic surfaces. A pipette was used to apply enough solution to cover the surface, with excess being drawn back up into the pipette. The wet item was then placed in a dark cupboard to dry at room temperature, and, once dry, the item was transferred to
a windowsill, as sunlight was shown to produce optimum developed marks. Any results were recorded using DCS-3. Both of the solutions were tested on each different surface type. 2.3.5. Superglue fuming The items were placed in a Mason Vactron MVC3000 fuming chamber, and six drops of Permabond Engineering Adhesive CPP621 Cyanoacrylate Adhesive placed in the foil tray. Auto cycle was used, with the settings for each cycle as shown in Table 1. Upon completion of the treatment, the items were removed and examined under white and fluorescent light, with any results recorded using DCS-3. 2.3.6. Sequential treatments In addition to individual treatments, sequential treatments using superglue, ninhydrin and silver nitrate solution were also undertaken in accordance with published procedures [11]. Between each treatment, the surfaces were examined under fluorescence and any developed marks recorded using DCS-3. Also, Sirchie Fluorescent Latent Print Powder in green-escent and Sirchie Magnetic Latent Print Powders in silver/black and silver/red were applied using a squirrel brush or magnetic wand as appropriate to marks developed through superglue fuming. Any marks developed were recorded using DCS-3. 2.3.7. Recovery of developed powder marks After the powder had been applied, a strip of J-Lar tape or a Crystal eezie tabs was removed from the roll or backing (as appropriate) and placed on the area. When lifting, a smooth lift was achieved by running the thumb across the tape in conjunction with the lifting action. Using Isomark™ T-1 Rapid Grey High Resolution Forensic Impression Material and a 50 ml Isomark™ Dispersing Gun fitted with a small Isomark™ nozzle, a layer of the silicone casting material was dispensed over the surface, ensuring that the mark was covered. The material was allowed to dry for a minimum of 3 min, before being peeled off, and any marks recorded using DCS-3. 3. Results 3.1. Analysis of results Images of the results were recorded using DCS-3, and the quality of the marks was assessed utilising the system as described by Sears et al. [6]: Grade 0 Grade 1 Grade 2 Grade 3 Grade 4
indicates no fingermark development; shows evidence of a fingermark having been deposited, but with an absence of ridge detail; contains limited detail, rendering the mark unsuitable for identification purposes; shows more evidence of ridge detail, ideal for identification; essentially presents as a complete fingermark, ideal for identification.
3.2. Individual treatments Before using the fluorescent fingerprint powder, it was necessary to determine the most effective of the three powders for the purpose. The recommended illumination for these powders is in the ultraviolet or Table 1 Settings used for each cycle of superglue treatment. Cycle
Hot plate temperature (°C)
Relative humidity (%)
Time (min)
Humidify Glue Purge
19–20 120 Decreasing from 120
– 80 80
15 15 20
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Fig. 1. (From left) RED-, PINK- and GREEN-escent powders on limestone showing developed finger marks varying in quality under illumination by a blue Crime-lite®.
blue region of the spectrum (254–525 nm) to activate the fluorescence and so a blue Crime-lite® was chosen as an illumination source. Fig. 1 shows samples of the results from the initial tests. It was determined that the GREEN-escent powder had more fluorescence and that ridge detail had better emphasis under fluorescence when compared to the RED- and PINK-escent powders. Table 2 gives an overview of the results based on the scoring guide. The values given for average successful grade are averages of all the positive enhancements for each treatment that produced positive results on a minimum of three separate occasions. The fluorescent fingerprint powder provided exceptional results on limestone, as did superglue, an exemplar of which is demonstrated in Fig. 2. Silver nitrate solution for hydrophobic surfaces proved to be beneficial for enhancing marks on brick, whilst producing lower quality results on sandstone. Example images of silver nitrate developed marks are given in Fig. 3. As is to be expected, a significant difference in quality was observed between a fingermark developed when the surface of the limestone was rough and a fingermark developed when the surface was relatively smooth (Fig. 4). Whilst ridge detail in image (a) can be clearly defined and the edges of the area where a fingermark was deposited are visible, in image (b) no ridge detail can be identified within the area of deposition.
by silver nitrate and superglue followed by ninhydrin and then silver nitrate. Instead of further enhancing the already developed marks, it was observed that the additional treatments had a destructive effect, resulting in no visible fingermarks. 3.4. Collection of developed fingermarks In addition to recording the developed fingermarks by photographing with the DCS-3, alternative methods (Isomark™, Crystal eezie tabs and J-Lar tape) were examined for the purpose of recovering any developed marks, as demonstrated in Table 3. The results show that Isomark™ was the only recovery medium trialled that produced a result (Fig. 5). 4. Discussion The methods used for the purpose of this study (fluorescence examination, fluorescent powders, ninhydrin, and superglue fuming) were chosen as they are the treatments commonly used in police force fingerprint laboratories or by crime scene investigators. Silver nitrate was included in this study due to the ability to adapt the original solution so that it would be suitable for both porous and non-porous surfaces. These solutions also had the advantage that they were easy to prepare and had previously shown positive results [12].
3.3. Sequential treatments The nature of the marks developed by superglue fuming on limestone resulted in a lack of contrast, creating difficulties in the recording process. In an attempt to further enhance the treated marks a range of sequential treatments were attempted. These consisted of development using superglue followed by fingerprint powders; ninhydrin followed
4.1. Fluorescent powders The benefit of using fluorescent fingerprint powder over the standard carbon-based powder commonly used by crime scene investigators was the finer consistency of the fluorescent powder [13], meaning
Table 2 Average results for treatments used individually on each surface. Brick
Limestone
Grade of marks achieved
Fluorescence Fluorescent powder Ninhydrin Silver Nitrate (hydrophobic) Silver nitrate (porous) Superglue
0
1–2
3–4
30 60 31 25 12 32
0 0 2 3 2 3
0 0 0 1 0 0
Rate of success (%)
– – – 13.8 – 8.6
Sandstone
Average successful grade
Grade of marks achieved 0
1–2
3–4
– – – 2.5 – 1.7
47 12 29 29 14 25
0 4 4 0 0 9
0 7 0 0 0 1
Rate of success (%)
– 47.8 12.1 – – 28.6
Average successful grade
Grade of marks achieved 0
1–2
3–4
– 2.8 1.3 – – 2
47 23 32 28 13 30
0 0 1 0 1 5
0 0 0 1 0 0
Rate of success (%)
Average successful grade
– – – – – 14.3
– – – – – 1
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L. Davis, R. Fisher / Science and Justice 55 (2015) 97–102
Fig. 2. Fingermark developed on limestone using superglue fuming.
that the powder required less ‘spreading’ on the surface, lessening the possibility of damage occurring during development of the fingermark. However, the method was not without its challenges. GREEN-escent contaminated surfaces very easily with an action as simple as opening the container and removing the lid. This contamination caused problems, as it mixed with other powders that were being used to treat other areas in close proximity or in the course of other treatments at later stages. Work should therefore be performed on a downdraft bench wherever possible. Additionally, the risk of damage to the fingermark was increased as the fluorescent fingerprint powder was manually applied with a squirrel brush, which can not only push powder into the texture of the surface (reducing the contrast between the mark and the substrate) but can also potentially cause the fingermark residue to spread and distort or destroy the ridge detail. Future studies would instead look at the use of magnetic fluorescent powders in order to allow application with a magnetic applicator, hopefully reducing both the amount of powder deposited on the background and also reducing potential damage to any fingermark residue. When applied to stronger fingermark depositions on a relatively smooth limestone surface, the results produced (as demonstrated in Table 2 and Fig. 5(a)) were of exceptionally high quality, supporting the theory described in the literature [13]. However, the texture of the surface had a significant effect on the quality of the fingermark. The reaction with the rougher limestone surface was similar to that with sandstone and brick—lacking in ridge detail, with a higher concentration of powder in the roughest areas. In addition, with the sandstone
Fig. 4. Fingermarks developed using green-escent powder on smooth limestone (left) and rough limestone (right) under illumination by a blue Crime-lite®.
surfaces in particular, the ease with which the powder spread was greatly decreased in comparison with the smoother areas of the limestone surfaces. Despite this, fluorescent fingerprint powders produced the best results when compared with the other treatments and surfaces used in the study. The results were marginally better than the superglue developed fingermarks, with the majority being suitable for comparison with other fingerprints. This increased performance over superglue may be as a result of the improved contrast when using fluorescence to visualise the developed marks.
4.2. Superglue fuming and sequential treatments In previous studies [4,5], superglue fuming resulted in a number of positive results on different stone types when dry, but has been unsuccessful at developing good quality marks on limestone. However, this study is the first report of high quality fingermarks being developed on limestone following treatment with superglue fuming. Unfortunately recording and recovery of these marks remain difficult due to lack of contrast. The method used for superglue fuming the items produced results of high quality, but of poor contrast to the surface. This indicates that there is not a need for improvement of the fuming method itself, but in order to improve the contrast and aid recording of developed fingermark post-superglue fuming, the use of dyes such as basic red 2 and basic yellow 40 could be investigated. However, there is a good chance that these will result in excessive background staining due to the porous/ semi-porous nature of these surfaces. For this reason it may therefore be beneficial to explore the use of a one-step superglue treatment, where the fluorescent dye is incorporated into the superglue itself [14].
Table 3 Average results of lifting attempts. Medium
Treatment
Result
Eezie Tabs Isomark™
Fluorescent powder a Fluorescent powder a Silver nitrate b Superglue a Fluorescent powder a
0 3.2 0 0 0
J-Lar Fig. 3. Fingermarks developed using silver nitrate solution for hydrophobic surfaces on brick (left) and sandstone (right).
a b
From limestone. From brick and sandstone.
L. Davis, R. Fisher / Science and Justice 55 (2015) 97–102
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Improvements to the method may include the investigation into a single solution that was suitable for both surface types, and the method of application would ideally be revisited with submersion and brushing being possibilities [10]. Submersion was not used in this study due to the experimental constraints, but in reality would be a suitable application choice in operational environments as it enables the solution to coat every side of the item, maximising potential evidence recovery. It may also be possible to control and improve development by exposing samples to an ultraviolet light source. 4.4. Unsuccessful treatments
Fig. 5. Fingermarks developed using green-escent fluorescent fingerprint powder. Images show original fingermarks on limestone surface prior to recovery (top) and lift using silicone-based casting medium, Isomark™ (bottom. Note: mirror image shown to allow direct comparison).
The lack of positive results from the sequential treatments is in agreement with previous studies [5], but may still warrant further investigation. 4.3. Silver nitrate solutions The use of silver nitrate solutions as a treatment was described by Lee and Gaensslen [15] as being more of historical interest than a current treatment. However, Yamashita et al. [12] support the use of the treatment and the versatility of the solutions that can be prepared enables its use on multiple surface types. An uncontrollable variable that was a key factor for the development of the surfaces treated with silver nitrate solutions was the presence of sunlight which, due to the unpredictable characteristics of the British weather, was not constant. It was observed that higher quality fingermarks with a less developed background surface were produced when left in bright sunlight, while a lack of direct sunlight (which occurred more often) resulted in the surface of the item turning a darker colour with an absence of developed fingermarks. The results produced by the methanol-based silver nitrate solution for hydrophobic surfaces were of better quality on brick than on sandstone (Fig. 4), but neither was as high quality as those developed by superglue or fluorescent powder. The solution for porous surfaces did not produce reproducible results. The method used for applying the two solutions was through the use of a pipette. Spraying and pouring were trialled but neither technique produced results and both were considerably messier when trying to coat a specific area. In addition, the time that the surfaces took to dry was extended when using the solution for porous surfaces on each of the items, with the solution appearing to sit on the surface, unlike the solution for hydrophobic surfaces which was quickly absorbed.
Ninhydrin and pre-treatment fluorescence examination proved to be largely unsuccessful. Some positive results were obtained with ninhydrin but the results were not reproduced sufficiently in the repeats of the experiments, suggesting that the treatments are not effective when used on the investigated surfaces. When heating the surfaces treated with ninhydrin it was common for water to either collect on or run across the surface (dependent upon the position the item was in) which, in some cases, saw the removal of the ninhydrin coating from the surface and could have resulted in diffusion of any amino acids present and the destruction of the fingermarks. This issue is believed to be due to the thermal mass of the brick or stone not being given sufficient time to reach the temperature of the oven, resulting in the humid air condensing on the cooler surface of the stone. CAST describe a method of avoiding this by placing the article in the oven at the required temperature without humidity until the temperature has equilibrated, then raising the temperature to get the reaction to proceed [16]. This is likely to produce better results and will be explored in future studies. Alternatively the marks could be developed without the application of heat, but this would result in a much longer development time that may not be suitable for operational settings. This may be a more suitable method in more temperate climates, where previous authors have seen some limited success with ninhydrin on limestone when analysing a larger data set [5]. 4.5. Recovery methods Prior to the success of Isomark™ two types of tapes, J-Lar and Crystal eezie tabs, were tested. It was observed that, on the limestone surfaces in particular, the fluorescent powder that had collected on the raised textured areas was being lifted rather than the developed fingermark. In light of this observation it was necessary to find a technique that would be able to get in to the crevices of the textured surface, thus ensuring maximum recovery of any developed fingermarks. In contrast to the results produced with the two types of tape, the results produced with the Isomark™ resulted in near exact replication of the original mark (Fig. 5). The issue was then the preservation of the surface of the cast, so as to avoid disruption of the mark either in transport or storage. Unlike recovering a mark with tape, the mark cannot easily be secured to an acetate sheet as the cast must be dry prior to removal from the surface. Therefore it would be necessary for an alternative method to be devised. Ideally, the cast would be secured to the base of a small box, or the possibility of securing a piece of tape over the mark could be explored in order to improve the practicality of the method. The use of a silicon-based casting material allows redevelopment of any finger marks as the method is non-destructive, while allowing for the production of high-resolution ridge detail [17]. While the technique proved invaluable in the recovery of fingermarks developed by fluorescent fingerprint powder on a relatively smooth limestone surface, the technique was less successful at recovering fingermarks developed by superglue fuming from limestone and silver nitrate from sandstone and brick. Shalhaub et al. [17] also describe an issue with using the Isomark™ similar to that experienced during this study. In the application of the
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L. Davis, R. Fisher / Science and Justice 55 (2015) 97–102
Isomark™ material, the formation of air bubbles in the cast can obscure ridge detail on the resulting cast, reducing the number of characteristics that can be used for comparison. This is represented by the irregular black areas within the friction ridge detail shown in Fig. 5(a). To improve the likelihood of air bubbles not occurring, great care needs to be exercised in the application of the material. It should be noted that all of the studies conducted in this research have been limited to relatively ‘fresh’ marks. Whilst this has provided valid results, it is important to remember that application in the field is also likely to require reliable techniques for older marks that have had a longer period between deposition and treatment. For this reason future studies would need to look at marks that have been aged for a variety of time intervals. This would not only give a more balanced view of whether a given technique is likely to be consistently successful or not, but may also reveal treatments that are more successful on older fingermarks (due to significant changes in the composition of the deposits). 5. Recommendations and conclusion The aim of the study conducted was to identify one or more suitable chemical treatments that could develop latent fingermarks on bricks and stones. To this end, three techniques have been identified— fluorescent fingerprint powder, silver nitrate and superglue, all of which are readily accessible to forensic scientists and have methods for preparation and use that are well established and relatively simple. In addition, it has been determined that the sequential treatments used provided no additional enhancement of developed fingermarks, making their use inappropriate for the sequential treatment of bricks and stones. The study has also gone beyond the aim laid out, by determining a recovery medium, Isomark™ T-1 Rapid Grey High Resolution Forensic Impression Material. In the process of completing the study a number of general challenges were faced. One such example was that, while asked to use a natural amount of force when depositing fingermarks on the surfaces and being carefully observed, each participant did not necessarily use a consistent amount of pressure with each donation potentially introducing a further variable and inconsistencies. However, the opportunities for the occurrence of errors were minimised through the repetition of the individual treatments for each donor and the use of the same solutions and equipment each time. The reproduction of the results therefore ensured the validity of any positive results. One way to minimise these inconsistencies in deposition pressure would be to use a fingerprint sampler, as described by Fieldhouse [18]. The limited nature of the study, using two stone types, one brick type and five fairly common treatments, only offers a small insight into the possibilities of bricks and stones as evidence opportunities. Yet the insight that is offered is one based on commonly accessible surfaces and has produced results that show the plausibility of the methods explored and the value of collecting such items for forensic investigation. Indeed, to the authors' knowledge, this is the only study that has reported any success in the recovery of fingermarks from house bricks using silver nitrate solution, with only one other study reporting successful recovery of fingermarks from house brick (in that case using iodinebenzoflavone) [3]. It is also the only study to have highlighted the use
of fluorescent powders in this area, particularly in combination with Isomark™ T-1 Rapid Grey High Resolution Forensic Impression Material. The results of the study have therefore been largely positive, with suggestions made as to the viability of using common treatments for the enhancement of latent fingermarks on bricks and stones. In light of this, the authors would like to recommend further investigation into the area (particularly looking at longer deposition intervals) and the consideration of implementing systems in police forces for the collection of bricks and stones. This would hopefully provide greater resilience towards crime, such as that seen in the UK riots in August 2011, and would aid in maximising evidence recovery from a largely underutilised source. Acknowledgements The authors would like to offer their thanks to S. Bleay, Centre for Applied Sciences and Technology (CAST) for his advice on this work. References [1] E.W. Durnal, Crime scene investigation (as seen on TV), Forensic Sci. Int. 199 (1) (2010) 1–5. [2] Staffordshire Fire and Rescue Service, Firefighters Attacked on Bonfire Night [online], Staffordshire Fire and Rescue Service, 2012. (Available at: http://www. staffordshirefire.gov.uk/2424.asp). [3] K. Flynn, P. Maynard, E.D. Pasquier, C. Lennard, M. Stoilovic, C. Roux, Evaluation of iodine-benzoflavone and ruthenium tetroxide spray reagents for the detection of latent fingermarks at the crime scene, J. Forensic Sci. 49 (4) (2004) 707–715. [4] A. Donche, S. Loyan, Development of latent fingerprints on stones, J. Forensic Identif. 46 (5) (1996) 542–555. [5] I. Hefetz, A. Cohen, Y. Cohen, A. Chaikovsky, Development of latent fingermarks from rocks and stones, J. Forensic Sci. (2014). http://dx.doi.org/10.1111/1556-4029.12438. [6] V.G. Sears, S.M. Bleay, H.L. Bandey, V.J. Bowman, A methodology for finger mark research, Sci. Justice 52 (3) (2012) 145–160. [7] V. Bowman, Manual of Fingerprint Development Techniques, second ed. Home Office Scientific Development Branch, Sandridge, UK, 2004. [8] A.R.W. Jackson, J.M. JACKSON, Forensic Science, second ed. Pearson Education Limited, Essex, UK, 2008. [9] S.M. Bleay, V.G. Sears, H.L. Bandey, A.P. Gibson, V.J. Bowman, R. Downham, L. Fitzgerald, T. Ciuksza, J. Ramadani, C. Selway, Fingerprint Source Book, Home Office Centre for Applied Science and Technology (CAST), 2012. 112–113. [10] T.A. Trozzi, R.L. Schwartz, M.L. Hollars, Standard processes, in: L.D. Leighton, Y.E. Trozzi, C. Wade (Eds.), Processing Guide for Developing Latent Prints, US Department of Justice, Federal Bureau of Investigation Laboratory Division, Washington, DC, 2000, pp. 38–39. [11] C. Champod, C.J. Lennard, P. Margot, M. Stoilovic, Fingerprints and Other Ridge Skin Impressions, CRC Press, Boca Raton, Florida, USA, 2004. [12] B. Yamashita, M. French, Latent print development, The Fingerprint Sourcebook, National Institute of Justice, Washington, DC, USA, 2011 (7-1-7-67). [13] V. Bowman, Fingerprint Development Handbook, second ed. Home Office Scientific Development Branch, Sandridge, UK, 2005. [14] C. Prete, L. Galmiche, F.-G. Quenum-Possy-Berry, C. Allain, N. Thiburce, T. Colard, Lumicyano™: a new fluorescent cyanoacrylate for a one-step luminescent latent fingermark development, Forensic Sci. Int. 233 (1) (2013) 104–112. [15] H.C. Lee, R.E. Gaensslen, Methods of latent fingerprint development, in: H.C. Lee, R. Ramotowski, R.E. Gaensslen (Eds.), Advances in Fingerprint Technology, second ed. CRC Press, Boca Raton, Florida, USA, 2001, pp. 105–150 (172). [16] S.M. Bleay, V.G. Sears, H.L. Bandey, A.P. Gibson, V.J. Bowman, R. Downham, L. Fitzgerald, T. Ciuksza, J. Ramadani, C. Selway, Fingerprint Source Book, Home Office Centre for Applied Science and Technology (CAST), 2012. 117. [17] R. Shalhoub, I. Quinones, C. Ames, B. Multaney, S. Curtis, H. Seeboruth, S. Moore, B. Daniel, The recovery of latent fingermarks and DNA using a silicone-based casting material, Forensic Sci. Int. 178 (2) (2008) 199–203. [18] S. Fieldhouse, Consistency and reproducibility in fingermark deposition, Forensic Sci. Int. 207 (1) (2011) 96–100.
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Fingermark recovery from riot debris: Bricks and stones Lisa Davis ⁎, Ruth Fisher Nottingham Trent University, United Kingdom
a r t i c l e
i n f o
Article history: Received 12 September 2014 Received in revised form 6 January 2015 Accepted 20 January 2015 Keywords: Bricks and stones Casting material Fingermark recovery Fluorescent powder Silver nitrate Superglue
a b s t r a c t During the UK riots in August 2011, large volumes of bricks and stones were used as weapons or projectiles in acts of violence or to gain illegal entry to properties. As a result, it has been emphasised that it is necessary to determine suitable chemical treatment(s) that will enable the development of fingermarks on such items in order to identify those involved. This study has undertaken the task of attempting to develop latent fingermarks on common house bricks, limestone and sandstone using current techniques including ninhydrin and fluorescence. Results produced have shown that, with fluorescent fingerprint powder, silver nitrate and superglue providing the best results, it is now possible to enhance fingermarks that were previously left undeveloped. In addition, Isomark T-1 Rapid Grey High Resolution Forensic Impression Material has proved extremely effective as an alternative method of recovering fingermarks developed with fluorescent fingerprint powder. © 2015 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.
1. Introduction Fingermark evidence has been well established in the criminal justice system for over a century. However, with the raised profile of forensic techniques among the population, and the heightened awareness of criminals, it has become necessary to investigate new, less known opportunities for acquiring evidence [1]. One such opportunity is in the recovery of fingermarks from difficult surfaces, such as bricks and stones. Bricks and stones are common artefacts in non-violent crimes such as burglary and theft from motor vehicles, as they are widely available and are ideal items for breaking glass to gain entry. The artefacts are also used in violent crimes, commonly as projectile weapons, most notably in the pursuit of attacking emergency services. This type of violence in the UK peaked in the civil unrest in August 2011, with rioting breaking out in cities across the country, and attacks on emergency services remain commonplace [2]. Despite their wide use in criminal activities, it has long been the accepted view of law enforcement agencies that these surfaces are unsuitable for fingermark recovery. However, preliminary studies have shown that this may not be the case and that, under certain circumstances, fingermark recovery may be possible [3–5].
⁎ Corresponding author. Tel.: +44 7921183068. E-mail address: [email protected] (L. Davis).
The aim of this study was to find appropriate treatment(s) for the enhancement of latent fingermarks on a range of brick and stone surfaces. This was undertaken in three objectives: - To find suitable chemical treatment(s) for the surfaces of bricks and stones; - To explore the suitability of using effective chemical treatments(s) in sequence; and - To find the chemical treatment(s) that produces optimum results in the enhancement of latent fingermarks on bricks and stones.
2. Materials and methods 2.1. Materials A total of ten participants donated fingermarks for the purpose of development in the study. The participants consisted of two males and eight females, aged between 18 and 40 years of age, who varied in donor strength. The participants were predominantly White British, and included smokers, vegetarians, and those who took regular medication. All participants signed consent forms and were assigned a Donor Identification Number to provide anonymity. A single type of brick was tested, common house brick, retrieved from a domestic garden in North Yorkshire. In addition, sandstone and limestone were also tested and were obtained from a local B&Q store in the form of paving stones. Each experiment was repeated a minimum of three times.
http://dx.doi.org/10.1016/j.scijus.2015.01.006 1355-0306/© 2015 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.
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2.2. Deposition of fingermarks Each participant was asked to wash their hands a half hour before donation, as recommended by Sears et al. [6], and to avoid touching their face in the intervening period. The participants were subsequently asked to deposit fingermarks by pressing the volar pad area of their finger(s) in the assigned area using a natural amount of pressure (approximately 400 g on a standard balance). All marks were treated within 24 h of deposition unless stated otherwise. 2.3. Post-deposition treatment methods 2.3.1. Examination under fluorescence Using Foster and Freeman Crime-lite®, four wavelength ranges were used to examine each of the surface types—blue (430 – 470 nm), violet (400 – 430 nm), green (500 – 550 nm) and blue–green (460 – 510 nm), with goggles containing orange (GG495), pale yellow (GG455), orange/ red (OG570) and orange (OG550) viewing filters, respectively [7]. Surfaces were examined both pre- and post-treatment, with each surface being searched using the grid method [8], recording any results using Foster and Freeman DCS-3 camera equipment. 2.3.2. Fluorescent fingerprint powders Sirchie Fluorescent Latent Print Powders, in ‘GREENescent’, ‘PINKescent’ and ‘REDescent’, were applied using squirrel hair brushes. A small amount of powder was transferred to a brush, and a little placed at the edge of the square being treated and brushed across the surface. To remove excess powder, and to spread powder on rougher surfaces, a circular motion was used rather than a sweeping motion. After application, the area was examined under fluorescence, with the appropriate goggles, with any results recorded using DCS-3. Initially the three powders were tested on limestone to determine the most effective under fluorescence, as limestone provided the smoothest surface and therefore the most likely to give positive results. Consequently, the most effective was used on sandstone and limestone, whilst all three were used on brick. 2.3.3. Ninhydrin The ninhydrin formulation used was that recommended by the Home Office [9], consisting of 25 g ninhydrin dissolved in absolute ethanol, ethyl acetate and acetic acid and then further diluted with HFE7100 to provide a working solution. The working solution was applied to the surface of each item using a pipette, ensuring that enough was applied so that the whole area was just wet. The surface was allowed to dry, before being transferred to the Weiss Gallenkamp oven, set to ninhydrin process, at a temperature of 80 °C and a relative humidity of 65% [7]. The items were placed on the shelf, with the treated surface perpendicular to the shelf, and left in the oven for 15 min. At the end of the 15 min, the items were removed from the oven, and allowed to cool, before examination under both white and fluorescent light, and any results recorded using DCS-3. 2.3.4. Silver nitrate Two solutions were prepared using the methods described by Trozzi, Schwartz and Hollars [10]. In both of these, 30 g silver nitrate (reagent grade purity ≥ 99%) is dissolved, with stirring, in 1000 mL distilled water or 100 mL distilled water and 1000 mL ethanol, respectively. The first solution was designed for porous surfaces, while the other was designed for hydrophobic surfaces. A pipette was used to apply enough solution to cover the surface, with excess being drawn back up into the pipette. The wet item was then placed in a dark cupboard to dry at room temperature, and, once dry, the item was transferred to
a windowsill, as sunlight was shown to produce optimum developed marks. Any results were recorded using DCS-3. Both of the solutions were tested on each different surface type. 2.3.5. Superglue fuming The items were placed in a Mason Vactron MVC3000 fuming chamber, and six drops of Permabond Engineering Adhesive CPP621 Cyanoacrylate Adhesive placed in the foil tray. Auto cycle was used, with the settings for each cycle as shown in Table 1. Upon completion of the treatment, the items were removed and examined under white and fluorescent light, with any results recorded using DCS-3. 2.3.6. Sequential treatments In addition to individual treatments, sequential treatments using superglue, ninhydrin and silver nitrate solution were also undertaken in accordance with published procedures [11]. Between each treatment, the surfaces were examined under fluorescence and any developed marks recorded using DCS-3. Also, Sirchie Fluorescent Latent Print Powder in green-escent and Sirchie Magnetic Latent Print Powders in silver/black and silver/red were applied using a squirrel brush or magnetic wand as appropriate to marks developed through superglue fuming. Any marks developed were recorded using DCS-3. 2.3.7. Recovery of developed powder marks After the powder had been applied, a strip of J-Lar tape or a Crystal eezie tabs was removed from the roll or backing (as appropriate) and placed on the area. When lifting, a smooth lift was achieved by running the thumb across the tape in conjunction with the lifting action. Using Isomark™ T-1 Rapid Grey High Resolution Forensic Impression Material and a 50 ml Isomark™ Dispersing Gun fitted with a small Isomark™ nozzle, a layer of the silicone casting material was dispensed over the surface, ensuring that the mark was covered. The material was allowed to dry for a minimum of 3 min, before being peeled off, and any marks recorded using DCS-3. 3. Results 3.1. Analysis of results Images of the results were recorded using DCS-3, and the quality of the marks was assessed utilising the system as described by Sears et al. [6]: Grade 0 Grade 1 Grade 2 Grade 3 Grade 4
indicates no fingermark development; shows evidence of a fingermark having been deposited, but with an absence of ridge detail; contains limited detail, rendering the mark unsuitable for identification purposes; shows more evidence of ridge detail, ideal for identification; essentially presents as a complete fingermark, ideal for identification.
3.2. Individual treatments Before using the fluorescent fingerprint powder, it was necessary to determine the most effective of the three powders for the purpose. The recommended illumination for these powders is in the ultraviolet or Table 1 Settings used for each cycle of superglue treatment. Cycle
Hot plate temperature (°C)
Relative humidity (%)
Time (min)
Humidify Glue Purge
19–20 120 Decreasing from 120
– 80 80
15 15 20
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Fig. 1. (From left) RED-, PINK- and GREEN-escent powders on limestone showing developed finger marks varying in quality under illumination by a blue Crime-lite®.
blue region of the spectrum (254–525 nm) to activate the fluorescence and so a blue Crime-lite® was chosen as an illumination source. Fig. 1 shows samples of the results from the initial tests. It was determined that the GREEN-escent powder had more fluorescence and that ridge detail had better emphasis under fluorescence when compared to the RED- and PINK-escent powders. Table 2 gives an overview of the results based on the scoring guide. The values given for average successful grade are averages of all the positive enhancements for each treatment that produced positive results on a minimum of three separate occasions. The fluorescent fingerprint powder provided exceptional results on limestone, as did superglue, an exemplar of which is demonstrated in Fig. 2. Silver nitrate solution for hydrophobic surfaces proved to be beneficial for enhancing marks on brick, whilst producing lower quality results on sandstone. Example images of silver nitrate developed marks are given in Fig. 3. As is to be expected, a significant difference in quality was observed between a fingermark developed when the surface of the limestone was rough and a fingermark developed when the surface was relatively smooth (Fig. 4). Whilst ridge detail in image (a) can be clearly defined and the edges of the area where a fingermark was deposited are visible, in image (b) no ridge detail can be identified within the area of deposition.
by silver nitrate and superglue followed by ninhydrin and then silver nitrate. Instead of further enhancing the already developed marks, it was observed that the additional treatments had a destructive effect, resulting in no visible fingermarks. 3.4. Collection of developed fingermarks In addition to recording the developed fingermarks by photographing with the DCS-3, alternative methods (Isomark™, Crystal eezie tabs and J-Lar tape) were examined for the purpose of recovering any developed marks, as demonstrated in Table 3. The results show that Isomark™ was the only recovery medium trialled that produced a result (Fig. 5). 4. Discussion The methods used for the purpose of this study (fluorescence examination, fluorescent powders, ninhydrin, and superglue fuming) were chosen as they are the treatments commonly used in police force fingerprint laboratories or by crime scene investigators. Silver nitrate was included in this study due to the ability to adapt the original solution so that it would be suitable for both porous and non-porous surfaces. These solutions also had the advantage that they were easy to prepare and had previously shown positive results [12].
3.3. Sequential treatments The nature of the marks developed by superglue fuming on limestone resulted in a lack of contrast, creating difficulties in the recording process. In an attempt to further enhance the treated marks a range of sequential treatments were attempted. These consisted of development using superglue followed by fingerprint powders; ninhydrin followed
4.1. Fluorescent powders The benefit of using fluorescent fingerprint powder over the standard carbon-based powder commonly used by crime scene investigators was the finer consistency of the fluorescent powder [13], meaning
Table 2 Average results for treatments used individually on each surface. Brick
Limestone
Grade of marks achieved
Fluorescence Fluorescent powder Ninhydrin Silver Nitrate (hydrophobic) Silver nitrate (porous) Superglue
0
1–2
3–4
30 60 31 25 12 32
0 0 2 3 2 3
0 0 0 1 0 0
Rate of success (%)
– – – 13.8 – 8.6
Sandstone
Average successful grade
Grade of marks achieved 0
1–2
3–4
– – – 2.5 – 1.7
47 12 29 29 14 25
0 4 4 0 0 9
0 7 0 0 0 1
Rate of success (%)
– 47.8 12.1 – – 28.6
Average successful grade
Grade of marks achieved 0
1–2
3–4
– 2.8 1.3 – – 2
47 23 32 28 13 30
0 0 1 0 1 5
0 0 0 1 0 0
Rate of success (%)
Average successful grade
– – – – – 14.3
– – – – – 1
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Fig. 2. Fingermark developed on limestone using superglue fuming.
that the powder required less ‘spreading’ on the surface, lessening the possibility of damage occurring during development of the fingermark. However, the method was not without its challenges. GREEN-escent contaminated surfaces very easily with an action as simple as opening the container and removing the lid. This contamination caused problems, as it mixed with other powders that were being used to treat other areas in close proximity or in the course of other treatments at later stages. Work should therefore be performed on a downdraft bench wherever possible. Additionally, the risk of damage to the fingermark was increased as the fluorescent fingerprint powder was manually applied with a squirrel brush, which can not only push powder into the texture of the surface (reducing the contrast between the mark and the substrate) but can also potentially cause the fingermark residue to spread and distort or destroy the ridge detail. Future studies would instead look at the use of magnetic fluorescent powders in order to allow application with a magnetic applicator, hopefully reducing both the amount of powder deposited on the background and also reducing potential damage to any fingermark residue. When applied to stronger fingermark depositions on a relatively smooth limestone surface, the results produced (as demonstrated in Table 2 and Fig. 5(a)) were of exceptionally high quality, supporting the theory described in the literature [13]. However, the texture of the surface had a significant effect on the quality of the fingermark. The reaction with the rougher limestone surface was similar to that with sandstone and brick—lacking in ridge detail, with a higher concentration of powder in the roughest areas. In addition, with the sandstone
Fig. 4. Fingermarks developed using green-escent powder on smooth limestone (left) and rough limestone (right) under illumination by a blue Crime-lite®.
surfaces in particular, the ease with which the powder spread was greatly decreased in comparison with the smoother areas of the limestone surfaces. Despite this, fluorescent fingerprint powders produced the best results when compared with the other treatments and surfaces used in the study. The results were marginally better than the superglue developed fingermarks, with the majority being suitable for comparison with other fingerprints. This increased performance over superglue may be as a result of the improved contrast when using fluorescence to visualise the developed marks.
4.2. Superglue fuming and sequential treatments In previous studies [4,5], superglue fuming resulted in a number of positive results on different stone types when dry, but has been unsuccessful at developing good quality marks on limestone. However, this study is the first report of high quality fingermarks being developed on limestone following treatment with superglue fuming. Unfortunately recording and recovery of these marks remain difficult due to lack of contrast. The method used for superglue fuming the items produced results of high quality, but of poor contrast to the surface. This indicates that there is not a need for improvement of the fuming method itself, but in order to improve the contrast and aid recording of developed fingermark post-superglue fuming, the use of dyes such as basic red 2 and basic yellow 40 could be investigated. However, there is a good chance that these will result in excessive background staining due to the porous/ semi-porous nature of these surfaces. For this reason it may therefore be beneficial to explore the use of a one-step superglue treatment, where the fluorescent dye is incorporated into the superglue itself [14].
Table 3 Average results of lifting attempts. Medium
Treatment
Result
Eezie Tabs Isomark™
Fluorescent powder a Fluorescent powder a Silver nitrate b Superglue a Fluorescent powder a
0 3.2 0 0 0
J-Lar Fig. 3. Fingermarks developed using silver nitrate solution for hydrophobic surfaces on brick (left) and sandstone (right).
a b
From limestone. From brick and sandstone.
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Improvements to the method may include the investigation into a single solution that was suitable for both surface types, and the method of application would ideally be revisited with submersion and brushing being possibilities [10]. Submersion was not used in this study due to the experimental constraints, but in reality would be a suitable application choice in operational environments as it enables the solution to coat every side of the item, maximising potential evidence recovery. It may also be possible to control and improve development by exposing samples to an ultraviolet light source. 4.4. Unsuccessful treatments
Fig. 5. Fingermarks developed using green-escent fluorescent fingerprint powder. Images show original fingermarks on limestone surface prior to recovery (top) and lift using silicone-based casting medium, Isomark™ (bottom. Note: mirror image shown to allow direct comparison).
The lack of positive results from the sequential treatments is in agreement with previous studies [5], but may still warrant further investigation. 4.3. Silver nitrate solutions The use of silver nitrate solutions as a treatment was described by Lee and Gaensslen [15] as being more of historical interest than a current treatment. However, Yamashita et al. [12] support the use of the treatment and the versatility of the solutions that can be prepared enables its use on multiple surface types. An uncontrollable variable that was a key factor for the development of the surfaces treated with silver nitrate solutions was the presence of sunlight which, due to the unpredictable characteristics of the British weather, was not constant. It was observed that higher quality fingermarks with a less developed background surface were produced when left in bright sunlight, while a lack of direct sunlight (which occurred more often) resulted in the surface of the item turning a darker colour with an absence of developed fingermarks. The results produced by the methanol-based silver nitrate solution for hydrophobic surfaces were of better quality on brick than on sandstone (Fig. 4), but neither was as high quality as those developed by superglue or fluorescent powder. The solution for porous surfaces did not produce reproducible results. The method used for applying the two solutions was through the use of a pipette. Spraying and pouring were trialled but neither technique produced results and both were considerably messier when trying to coat a specific area. In addition, the time that the surfaces took to dry was extended when using the solution for porous surfaces on each of the items, with the solution appearing to sit on the surface, unlike the solution for hydrophobic surfaces which was quickly absorbed.
Ninhydrin and pre-treatment fluorescence examination proved to be largely unsuccessful. Some positive results were obtained with ninhydrin but the results were not reproduced sufficiently in the repeats of the experiments, suggesting that the treatments are not effective when used on the investigated surfaces. When heating the surfaces treated with ninhydrin it was common for water to either collect on or run across the surface (dependent upon the position the item was in) which, in some cases, saw the removal of the ninhydrin coating from the surface and could have resulted in diffusion of any amino acids present and the destruction of the fingermarks. This issue is believed to be due to the thermal mass of the brick or stone not being given sufficient time to reach the temperature of the oven, resulting in the humid air condensing on the cooler surface of the stone. CAST describe a method of avoiding this by placing the article in the oven at the required temperature without humidity until the temperature has equilibrated, then raising the temperature to get the reaction to proceed [16]. This is likely to produce better results and will be explored in future studies. Alternatively the marks could be developed without the application of heat, but this would result in a much longer development time that may not be suitable for operational settings. This may be a more suitable method in more temperate climates, where previous authors have seen some limited success with ninhydrin on limestone when analysing a larger data set [5]. 4.5. Recovery methods Prior to the success of Isomark™ two types of tapes, J-Lar and Crystal eezie tabs, were tested. It was observed that, on the limestone surfaces in particular, the fluorescent powder that had collected on the raised textured areas was being lifted rather than the developed fingermark. In light of this observation it was necessary to find a technique that would be able to get in to the crevices of the textured surface, thus ensuring maximum recovery of any developed fingermarks. In contrast to the results produced with the two types of tape, the results produced with the Isomark™ resulted in near exact replication of the original mark (Fig. 5). The issue was then the preservation of the surface of the cast, so as to avoid disruption of the mark either in transport or storage. Unlike recovering a mark with tape, the mark cannot easily be secured to an acetate sheet as the cast must be dry prior to removal from the surface. Therefore it would be necessary for an alternative method to be devised. Ideally, the cast would be secured to the base of a small box, or the possibility of securing a piece of tape over the mark could be explored in order to improve the practicality of the method. The use of a silicon-based casting material allows redevelopment of any finger marks as the method is non-destructive, while allowing for the production of high-resolution ridge detail [17]. While the technique proved invaluable in the recovery of fingermarks developed by fluorescent fingerprint powder on a relatively smooth limestone surface, the technique was less successful at recovering fingermarks developed by superglue fuming from limestone and silver nitrate from sandstone and brick. Shalhaub et al. [17] also describe an issue with using the Isomark™ similar to that experienced during this study. In the application of the
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Isomark™ material, the formation of air bubbles in the cast can obscure ridge detail on the resulting cast, reducing the number of characteristics that can be used for comparison. This is represented by the irregular black areas within the friction ridge detail shown in Fig. 5(a). To improve the likelihood of air bubbles not occurring, great care needs to be exercised in the application of the material. It should be noted that all of the studies conducted in this research have been limited to relatively ‘fresh’ marks. Whilst this has provided valid results, it is important to remember that application in the field is also likely to require reliable techniques for older marks that have had a longer period between deposition and treatment. For this reason future studies would need to look at marks that have been aged for a variety of time intervals. This would not only give a more balanced view of whether a given technique is likely to be consistently successful or not, but may also reveal treatments that are more successful on older fingermarks (due to significant changes in the composition of the deposits). 5. Recommendations and conclusion The aim of the study conducted was to identify one or more suitable chemical treatments that could develop latent fingermarks on bricks and stones. To this end, three techniques have been identified— fluorescent fingerprint powder, silver nitrate and superglue, all of which are readily accessible to forensic scientists and have methods for preparation and use that are well established and relatively simple. In addition, it has been determined that the sequential treatments used provided no additional enhancement of developed fingermarks, making their use inappropriate for the sequential treatment of bricks and stones. The study has also gone beyond the aim laid out, by determining a recovery medium, Isomark™ T-1 Rapid Grey High Resolution Forensic Impression Material. In the process of completing the study a number of general challenges were faced. One such example was that, while asked to use a natural amount of force when depositing fingermarks on the surfaces and being carefully observed, each participant did not necessarily use a consistent amount of pressure with each donation potentially introducing a further variable and inconsistencies. However, the opportunities for the occurrence of errors were minimised through the repetition of the individual treatments for each donor and the use of the same solutions and equipment each time. The reproduction of the results therefore ensured the validity of any positive results. One way to minimise these inconsistencies in deposition pressure would be to use a fingerprint sampler, as described by Fieldhouse [18]. The limited nature of the study, using two stone types, one brick type and five fairly common treatments, only offers a small insight into the possibilities of bricks and stones as evidence opportunities. Yet the insight that is offered is one based on commonly accessible surfaces and has produced results that show the plausibility of the methods explored and the value of collecting such items for forensic investigation. Indeed, to the authors' knowledge, this is the only study that has reported any success in the recovery of fingermarks from house bricks using silver nitrate solution, with only one other study reporting successful recovery of fingermarks from house brick (in that case using iodinebenzoflavone) [3]. It is also the only study to have highlighted the use
of fluorescent powders in this area, particularly in combination with Isomark™ T-1 Rapid Grey High Resolution Forensic Impression Material. The results of the study have therefore been largely positive, with suggestions made as to the viability of using common treatments for the enhancement of latent fingermarks on bricks and stones. In light of this, the authors would like to recommend further investigation into the area (particularly looking at longer deposition intervals) and the consideration of implementing systems in police forces for the collection of bricks and stones. This would hopefully provide greater resilience towards crime, such as that seen in the UK riots in August 2011, and would aid in maximising evidence recovery from a largely underutilised source. Acknowledgements The authors would like to offer their thanks to S. Bleay, Centre for Applied Sciences and Technology (CAST) for his advice on this work. References [1] E.W. Durnal, Crime scene investigation (as seen on TV), Forensic Sci. Int. 199 (1) (2010) 1–5. [2] Staffordshire Fire and Rescue Service, Firefighters Attacked on Bonfire Night [online], Staffordshire Fire and Rescue Service, 2012. (Available at: http://www. staffordshirefire.gov.uk/2424.asp). [3] K. Flynn, P. Maynard, E.D. Pasquier, C. Lennard, M. Stoilovic, C. Roux, Evaluation of iodine-benzoflavone and ruthenium tetroxide spray reagents for the detection of latent fingermarks at the crime scene, J. Forensic Sci. 49 (4) (2004) 707–715. [4] A. Donche, S. Loyan, Development of latent fingerprints on stones, J. Forensic Identif. 46 (5) (1996) 542–555. [5] I. Hefetz, A. Cohen, Y. Cohen, A. Chaikovsky, Development of latent fingermarks from rocks and stones, J. Forensic Sci. (2014). http://dx.doi.org/10.1111/1556-4029.12438. [6] V.G. Sears, S.M. Bleay, H.L. Bandey, V.J. Bowman, A methodology for finger mark research, Sci. Justice 52 (3) (2012) 145–160. [7] V. Bowman, Manual of Fingerprint Development Techniques, second ed. Home Office Scientific Development Branch, Sandridge, UK, 2004. [8] A.R.W. Jackson, J.M. JACKSON, Forensic Science, second ed. Pearson Education Limited, Essex, UK, 2008. [9] S.M. Bleay, V.G. Sears, H.L. Bandey, A.P. Gibson, V.J. Bowman, R. Downham, L. Fitzgerald, T. Ciuksza, J. Ramadani, C. Selway, Fingerprint Source Book, Home Office Centre for Applied Science and Technology (CAST), 2012. 112–113. [10] T.A. Trozzi, R.L. Schwartz, M.L. Hollars, Standard processes, in: L.D. Leighton, Y.E. Trozzi, C. Wade (Eds.), Processing Guide for Developing Latent Prints, US Department of Justice, Federal Bureau of Investigation Laboratory Division, Washington, DC, 2000, pp. 38–39. [11] C. Champod, C.J. Lennard, P. Margot, M. Stoilovic, Fingerprints and Other Ridge Skin Impressions, CRC Press, Boca Raton, Florida, USA, 2004. [12] B. Yamashita, M. French, Latent print development, The Fingerprint Sourcebook, National Institute of Justice, Washington, DC, USA, 2011 (7-1-7-67). [13] V. Bowman, Fingerprint Development Handbook, second ed. Home Office Scientific Development Branch, Sandridge, UK, 2005. [14] C. Prete, L. Galmiche, F.-G. Quenum-Possy-Berry, C. Allain, N. Thiburce, T. Colard, Lumicyano™: a new fluorescent cyanoacrylate for a one-step luminescent latent fingermark development, Forensic Sci. Int. 233 (1) (2013) 104–112. [15] H.C. Lee, R.E. Gaensslen, Methods of latent fingerprint development, in: H.C. Lee, R. Ramotowski, R.E. Gaensslen (Eds.), Advances in Fingerprint Technology, second ed. CRC Press, Boca Raton, Florida, USA, 2001, pp. 105–150 (172). [16] S.M. Bleay, V.G. Sears, H.L. Bandey, A.P. Gibson, V.J. Bowman, R. Downham, L. Fitzgerald, T. Ciuksza, J. Ramadani, C. Selway, Fingerprint Source Book, Home Office Centre for Applied Science and Technology (CAST), 2012. 117. [17] R. Shalhoub, I. Quinones, C. Ames, B. Multaney, S. Curtis, H. Seeboruth, S. Moore, B. Daniel, The recovery of latent fingermarks and DNA using a silicone-based casting material, Forensic Sci. Int. 178 (2) (2008) 199–203. [18] S. Fieldhouse, Consistency and reproducibility in fingermark deposition, Forensic Sci. Int. 207 (1) (2011) 96–100.