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Commentary on: Mark Benecke and Larry Barksdale, Distinction of bloodstain patterns from fly artifacts
Forensic Science International 149 (2005) 293–294
Discussion
Commentary on: Mark Benecke and Larry Barksdale, Distinction of bloodstain patterns from fly artifacts. Forensic Science International. 137(2003) 152–159 Ralph R. Ristenbatt IIIa,*, Peter A. Pizzolaa, Robert C. Shalerb, Louis N. Sorkinc a
Office of Chief Medical Examiner, Department of Investigations, Forensic Analysis and Reconstruction Unit, 520 First Avenue, New York, 10016, USA b Office of Chief Medical Examiner, Department of Forensic Biology, 520 First Avenue, New York, 10016, USA c American Museum of Natural History, Division of Invertebrate Zoology, Entomology Section, Central Park West at 79th Street, New York, NY 10024, USA Received 26 April 2004; accepted 5 November 2004 Available online 23 August 2004
Sir, Crime scene and incident reconstruction rely upon the analysis of bloodstain patterns and other physical evidence by experienced and competent criminalists, conversant in the many disciplines of forensic science. In a recent issue of Forensic Science International, Benecke and Barksdale [1] provide a methodology for distinguishing blood spatter patterns from stain patterns produced by flies ingesting blood at a scene. The article has some merit, however, the authors attempt to simplify bloodstain pattern analysis, supplanting science with rote procedure. First, the authors cite Ristenbatt and Shaler [2] erroneously, implying this case occurred outside of the United States. In fact, it was a New York City case and it involved no entomological evidence. Second, they assert that there has been no integrated approach between criminalists and natural scientists. This is simply not true. The importance of differentiating insect artifacts from bloodstain patterns has been discussed [3–6], demonstrating cooperation between criminalists and entomologists prior to this work. In 1996, collaborative work between the Office of Chief Medical Examiner and the American Museum of Natural History in New York City examined artifacts produced by cockroaches that resembled human bloodstains [5,6]. This study was conducted after encountering interesting bloodstain patterns in unexpected locations at several crime scenes. * Corresponding author. Tel.: þ1-212-447-2030; fax: þ1-212-447-2039. E-mail address: [email protected] (R.R. Ristenbatt III).
Furthermore, the authors unfortunately adhere to the inadequate and imprecise low- , medium- , and high-velocity definitions. Interestingly, they sub-classify these patterns using narrowly defined ranges of spot size. Furthermore, they categorize stains resulting from ‘‘free-falling’’ and ‘‘cast-off’’ blood as low-velocity spatter, which we find disturbing and incorrect as there is no impact associated with either of these modes of deposition. Also troubling, with respect to the first case they discuss, the authors use the phrase ‘‘slinging of a lot of blood around.’’ Without the benefit of illustrations, one cannot be sure how this observation suggests not only gunshot wounds, but also the ‘‘considerable movement of the victim and suspect(s).’’ Moreover, it is impossible to imagine how these bloodstains, even if represented, could suggest a possible motive for the attack. The authors also attempt to reconstruct the angle of impact from a pattern of blood droplet stains that showed no apparent point of convergence. Regarding Case III, the author’s primary conclusion is flawed. They state that a pattern of ‘‘tiny, round stains on the lamp were distributed over the complete surface’’ is likely the result of blood ‘‘cast-off’’ from a knife. They further state that these small stains were found ‘‘all over the lamp, on all sides, including top and bottom.’’ They describe the lamp as being ‘‘in the height of an adult central European person’s head’’ (approximately 1.8 m) but neglect to inform the reader of the victim’s height. They failed to describe the size of the stains, however, an illustration depicts two of the stains as l mm. If these stains are all approximately
0379-0738/$ – see front matter # 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.forsciint.2004.05.012
294
R.R. Ristenbatt III et al. / Forensic Science International 149 (2005) 293–294
identical in size and distribution, and the lamp (shade?) is not flat, it is impossible for these stains to have formed as the authors describe. Their hypothesis regarding the production of the ‘‘castoff’’ droplets and the manner in which they were deposited (while lamp is rotating) is incorrect. Specifically, their application of the term ‘‘high-velocity’’ to an arc or ‘‘cast-off’’ pattern, referring to the velocity of blood droplets leaving the knife rather than the velocity of an object impacting a source of blood is in error. It is not possible to create an even distribution of tiny blood droplets on all surfaces of a lamp, even with rotation. Some of these droplets would strike the lamp at oblique angles, resulting in elongated stains. Only one of six stains DNA typed yielded a result. Furthermore, studies [5,6] have shown that ‘‘insect stains’’ often yield positive presumptive and confirmatory tests for blood, but they rarely yield DNA types. It is also known that flies often alight near warm surfaces such as lamps [1,3,4]. Additionally, if Benecke and Barksdale are correct that the lamp was rotating while blood droplets were impacting the surface they have completely ignored the influence of a moving target on the resulting stain patterns, which must be considered [7]. To opine that it is unlikely that these stains were caused by flies because of the season (winter) and that no ‘‘rotting organic material’’ existed is a mistake. Flies and other insects commonly hibernate in warm domiciles during cold seasons. They do appear sporadically during the winter in a warm residence after waking. It has been reported that certain overwintered calliphorid species become active as soon as ground temperature reaches 5 8C and would soon need to feed due to depleted stored fat that had occurred during the overwintering period [8]. In fact, flies will become active on warm, winter days and can be found walking or flying on these occasions in the home or work office. Depending on the interval between time of death and discovery of the body, a small number of flies could produce the pattern described. Benecke and Barksdale conclude their work with guidelines to differentiate fly artifacts from patterns of human blood. In item number 4 on their list they state ‘‘stains that have a tail/body (Ltl/Lb) ratio greater than one’’ and ‘‘any stains without a distinguishable tail and body’’ should be eliminated as ‘‘human bloodstain patterns.’’ These are misleading and dangerous statements. Frequently, collision of an airborne blood droplet with a surface at an oblique angle,
such as 708 from the normal, will produce a stain with a tail/ body ratio greater than one. It is unclear what the authors are referring to with the latter statement, as a stain without a distinguishable tail and body cannot exist, since all stains must have a ‘‘body.’’ In item number five the authors imply that ‘‘cast-off’’ patterns of blood should possess ‘‘misting’’ around the concentrated mass. This is probably an oversight on their part as they were likely trying to associate misted blood with radial impact spatter patterns. To inexperienced criminalists and students, the authors correctly call attention to these frequently seen artifacts, especially in urban areas where flies and roaches are commonplace. Regrettably, there is misleading and erroneous information that an inexperienced criminalist may regard as fact. Unfortunately, the paper offers no new information. References [1] M. Benecke, L. Barksdale, Distinction of bloodstain patterns from fly artifacts, Forensic Sci. Int. 137 (2003) 152–159. [2] R.R. Ristenbatt III, R.C. Shaler, A bloodstain pattern interpretation in a homicide case involving an apparent stomping, J. Forensic Sci. 40 (1995) 139–145. [3] T. Bevel, R. M. Gardner, Bloodstain pattern analysis with an introduction to crime scene reconstruction, CRC Press, Boca Raton, 1997. [4] S. H. James, W. G. Eckert, Interpretation of bloodstain evidence at crimes scenes, second ed., CRC Press, Boca Raton, 1998. [5] G. Montenegro, R. R. Ristenbatt, III, L. N. Sorkin, M. Dorokhov, L. Quarino, R. C. Shaler, Crime scene artefacts: Cockroach contributions, Paper presented at the 22nd Annual Meeting of the Northeastern Association of Forensic Scientists, Pocono Manor, PA, October 03–05, 1996. [6] R. R. Ristenbatt, III, L. N. Sorkin, M. Dorokhov, G. Montenegro, L. Quarino, R. C. Shaler, Crime scene artefacts: cockroach contributions, Paper presented at the 49th Annual Meeting of the American Academy of Forensic Sciences, New York City, NY, February 17–22, 1997. [7] P.A. Pizzola, S. Roth, P.R. De Forest, Blood droplet dynamicsII, J. Forensic Sci. 31 (1986) 50–64. [8] B. F. Prendergast, A. L. Rosales, E. S. Evans, Jr., Section 3 Important filth fly species, biology and behavior, in: B. F. Prendergast (Ed.) Filth Flies: Significance, Surveillance and Control in Contingency Operations, Technical Guide No. 30, Armed Forces Pest Management Board, Defense Pest Management Information Analysis Center, Forest Glen Section/Walter Reed Army Medical Center, Washington, DC, April 15, 2002, pp. 12–17.
Discussion
Commentary on: Mark Benecke and Larry Barksdale, Distinction of bloodstain patterns from fly artifacts. Forensic Science International. 137(2003) 152–159 Ralph R. Ristenbatt IIIa,*, Peter A. Pizzolaa, Robert C. Shalerb, Louis N. Sorkinc a
Office of Chief Medical Examiner, Department of Investigations, Forensic Analysis and Reconstruction Unit, 520 First Avenue, New York, 10016, USA b Office of Chief Medical Examiner, Department of Forensic Biology, 520 First Avenue, New York, 10016, USA c American Museum of Natural History, Division of Invertebrate Zoology, Entomology Section, Central Park West at 79th Street, New York, NY 10024, USA Received 26 April 2004; accepted 5 November 2004 Available online 23 August 2004
Sir, Crime scene and incident reconstruction rely upon the analysis of bloodstain patterns and other physical evidence by experienced and competent criminalists, conversant in the many disciplines of forensic science. In a recent issue of Forensic Science International, Benecke and Barksdale [1] provide a methodology for distinguishing blood spatter patterns from stain patterns produced by flies ingesting blood at a scene. The article has some merit, however, the authors attempt to simplify bloodstain pattern analysis, supplanting science with rote procedure. First, the authors cite Ristenbatt and Shaler [2] erroneously, implying this case occurred outside of the United States. In fact, it was a New York City case and it involved no entomological evidence. Second, they assert that there has been no integrated approach between criminalists and natural scientists. This is simply not true. The importance of differentiating insect artifacts from bloodstain patterns has been discussed [3–6], demonstrating cooperation between criminalists and entomologists prior to this work. In 1996, collaborative work between the Office of Chief Medical Examiner and the American Museum of Natural History in New York City examined artifacts produced by cockroaches that resembled human bloodstains [5,6]. This study was conducted after encountering interesting bloodstain patterns in unexpected locations at several crime scenes. * Corresponding author. Tel.: þ1-212-447-2030; fax: þ1-212-447-2039. E-mail address: [email protected] (R.R. Ristenbatt III).
Furthermore, the authors unfortunately adhere to the inadequate and imprecise low- , medium- , and high-velocity definitions. Interestingly, they sub-classify these patterns using narrowly defined ranges of spot size. Furthermore, they categorize stains resulting from ‘‘free-falling’’ and ‘‘cast-off’’ blood as low-velocity spatter, which we find disturbing and incorrect as there is no impact associated with either of these modes of deposition. Also troubling, with respect to the first case they discuss, the authors use the phrase ‘‘slinging of a lot of blood around.’’ Without the benefit of illustrations, one cannot be sure how this observation suggests not only gunshot wounds, but also the ‘‘considerable movement of the victim and suspect(s).’’ Moreover, it is impossible to imagine how these bloodstains, even if represented, could suggest a possible motive for the attack. The authors also attempt to reconstruct the angle of impact from a pattern of blood droplet stains that showed no apparent point of convergence. Regarding Case III, the author’s primary conclusion is flawed. They state that a pattern of ‘‘tiny, round stains on the lamp were distributed over the complete surface’’ is likely the result of blood ‘‘cast-off’’ from a knife. They further state that these small stains were found ‘‘all over the lamp, on all sides, including top and bottom.’’ They describe the lamp as being ‘‘in the height of an adult central European person’s head’’ (approximately 1.8 m) but neglect to inform the reader of the victim’s height. They failed to describe the size of the stains, however, an illustration depicts two of the stains as l mm. If these stains are all approximately
0379-0738/$ – see front matter # 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.forsciint.2004.05.012
294
R.R. Ristenbatt III et al. / Forensic Science International 149 (2005) 293–294
identical in size and distribution, and the lamp (shade?) is not flat, it is impossible for these stains to have formed as the authors describe. Their hypothesis regarding the production of the ‘‘castoff’’ droplets and the manner in which they were deposited (while lamp is rotating) is incorrect. Specifically, their application of the term ‘‘high-velocity’’ to an arc or ‘‘cast-off’’ pattern, referring to the velocity of blood droplets leaving the knife rather than the velocity of an object impacting a source of blood is in error. It is not possible to create an even distribution of tiny blood droplets on all surfaces of a lamp, even with rotation. Some of these droplets would strike the lamp at oblique angles, resulting in elongated stains. Only one of six stains DNA typed yielded a result. Furthermore, studies [5,6] have shown that ‘‘insect stains’’ often yield positive presumptive and confirmatory tests for blood, but they rarely yield DNA types. It is also known that flies often alight near warm surfaces such as lamps [1,3,4]. Additionally, if Benecke and Barksdale are correct that the lamp was rotating while blood droplets were impacting the surface they have completely ignored the influence of a moving target on the resulting stain patterns, which must be considered [7]. To opine that it is unlikely that these stains were caused by flies because of the season (winter) and that no ‘‘rotting organic material’’ existed is a mistake. Flies and other insects commonly hibernate in warm domiciles during cold seasons. They do appear sporadically during the winter in a warm residence after waking. It has been reported that certain overwintered calliphorid species become active as soon as ground temperature reaches 5 8C and would soon need to feed due to depleted stored fat that had occurred during the overwintering period [8]. In fact, flies will become active on warm, winter days and can be found walking or flying on these occasions in the home or work office. Depending on the interval between time of death and discovery of the body, a small number of flies could produce the pattern described. Benecke and Barksdale conclude their work with guidelines to differentiate fly artifacts from patterns of human blood. In item number 4 on their list they state ‘‘stains that have a tail/body (Ltl/Lb) ratio greater than one’’ and ‘‘any stains without a distinguishable tail and body’’ should be eliminated as ‘‘human bloodstain patterns.’’ These are misleading and dangerous statements. Frequently, collision of an airborne blood droplet with a surface at an oblique angle,
such as 708 from the normal, will produce a stain with a tail/ body ratio greater than one. It is unclear what the authors are referring to with the latter statement, as a stain without a distinguishable tail and body cannot exist, since all stains must have a ‘‘body.’’ In item number five the authors imply that ‘‘cast-off’’ patterns of blood should possess ‘‘misting’’ around the concentrated mass. This is probably an oversight on their part as they were likely trying to associate misted blood with radial impact spatter patterns. To inexperienced criminalists and students, the authors correctly call attention to these frequently seen artifacts, especially in urban areas where flies and roaches are commonplace. Regrettably, there is misleading and erroneous information that an inexperienced criminalist may regard as fact. Unfortunately, the paper offers no new information. References [1] M. Benecke, L. Barksdale, Distinction of bloodstain patterns from fly artifacts, Forensic Sci. Int. 137 (2003) 152–159. [2] R.R. Ristenbatt III, R.C. Shaler, A bloodstain pattern interpretation in a homicide case involving an apparent stomping, J. Forensic Sci. 40 (1995) 139–145. [3] T. Bevel, R. M. Gardner, Bloodstain pattern analysis with an introduction to crime scene reconstruction, CRC Press, Boca Raton, 1997. [4] S. H. James, W. G. Eckert, Interpretation of bloodstain evidence at crimes scenes, second ed., CRC Press, Boca Raton, 1998. [5] G. Montenegro, R. R. Ristenbatt, III, L. N. Sorkin, M. Dorokhov, L. Quarino, R. C. Shaler, Crime scene artefacts: Cockroach contributions, Paper presented at the 22nd Annual Meeting of the Northeastern Association of Forensic Scientists, Pocono Manor, PA, October 03–05, 1996. [6] R. R. Ristenbatt, III, L. N. Sorkin, M. Dorokhov, G. Montenegro, L. Quarino, R. C. Shaler, Crime scene artefacts: cockroach contributions, Paper presented at the 49th Annual Meeting of the American Academy of Forensic Sciences, New York City, NY, February 17–22, 1997. [7] P.A. Pizzola, S. Roth, P.R. De Forest, Blood droplet dynamicsII, J. Forensic Sci. 31 (1986) 50–64. [8] B. F. Prendergast, A. L. Rosales, E. S. Evans, Jr., Section 3 Important filth fly species, biology and behavior, in: B. F. Prendergast (Ed.) Filth Flies: Significance, Surveillance and Control in Contingency Operations, Technical Guide No. 30, Armed Forces Pest Management Board, Defense Pest Management Information Analysis Center, Forest Glen Section/Walter Reed Army Medical Center, Washington, DC, April 15, 2002, pp. 12–17.