ABSTRACT
In criminal cases, the bio-logical residues on bullets should be examined. In many cases, they may constitute a precious evidence. The aim of this study is to show how it is possible to gather evidence from biological residues. In order to achieve this purpose, we planned to fire test shots at animal tissues and exam-ine the bullets for residues belonging to the target.
50 test shots were fired with a 7.65 mm semi-automatic pistol. In some of these test shots, calf spleens were used as targets. The bullets obtained were coded. Sub-sequently, the bullets were examined without knowledge of whether they had hit the mark or not. The aim was to correctly guess those that had hit the mark. To this end, a commercial kit named Bluestar, which is a Luminol derivative, was used.
After the application of
Lu-minol, all the bullets showed blue luminescence in a dark environment. False positivi-ties could have resulted from gunpowder remnants or the metal of the bullet. In order to eliminate the false posi-tivities, the study should be repeated with equipment ca-pable of measuring the emis-sion intensity and spectrum of Luminol or with tests other than the Luminol test.
Key words: gunshot wounds,
biological residue, Luminol
ÖZET
Ateşli silah yaralanmalarında mermi çekirdeklerinin üzerinde biyolojik kalıntıların araştırılma-sı gereklidir. Birçok durumda bu, çok kıymetli bir delil oluş-turur. Bunun mümkün olduğu-nun gösterilmesi bu çalışmanın amacıdır. Bu amaçla hayvan do-kularına deneme atışları yapıla-rak mermi çekirdekleri üzerinde hedefe ait kalıntıların araştırıl-ması düşünülmüştür.
7.65 mm yarı otomatik bir ta-banca ile 50 deneme atışı yapıl-mıştır. Bu atışların bazılarında hedefe dana dalağı konulmuş-tur. Mermilerin hepsi kodlan-dıktan sonra hangilerinin dalak dokusuna isabet ettiği bilinme-den bunu doğru tahmin etmek üzere incelenmiştir. Bu amaçla Luminol türevi olan Bluestar isimli ticari kit kullanılmıştır. Luminol yöntemi ile dokuya isabet eden ve etmeyen bütün
mermi çekirdekleri karanlık ortamda mavi ışıma gösterdi. Yanlış pozitifliklerin nedeni ba-rut artıkları veya mermi göm-leği metali olabilir. Bu yanlış pozitiflikleri ekarte etmek için çalışmanın Luminol emisyon yoğunluğunu ve spektrumunu ölçebilecek ekipmanla veya Lu-minol testi dışındaki testlerle tekrar edilmesi gerekir.
Anahtar sözcükler: Ateşli silah
ya-raları, biyolojik kalıntı, Luminol > Prof.Dr. Yücel ARISOY1
1 Dokuz Eylül Üniversitesi Tıp Fakültesi Adli Tıp AD. İzmir
BIOLOGICAL RESIDUES
ON BULLETS
MERMİ ÇEKİRDEKLERİ ÜZERİNDEKİ
BİYOLOJİK KALINTILAR
INTRODUCTION
In criminal cases, the marks on a cartridge case or bullet are exa-mined to determine the firearm, from which the shot is fired. Es-pecially the consistency between the marks on the bullets obtai-ned from the wound site and the marks on the bullets fired in the test shots constitute the evidence that the shots were fired from a particular weapon.
However, if the bullet leaves the body, it is difficult to solve a cri-me. The ambiguities may still per-sist even if a suspected weapon or even a bullet or cartridge case is
found. Especially if multiple sus-pects and suspected weapons are present, the doubts can not be ru-led out. In such cases, the bullets found in the crime scene should be examined for biological dues. The determination of resi-dues on the bullet, which belong to the wounded person, constitu-tes an important evidence.
Accordingly, an experiment based on the investigation of bullets for residues belonging to the target was envisaged. In order to de-monstrate the presence of blo-od stains on the bullets, the use of a presumptive blood test was envisaged. Luminol (5-amino-2, 3-dihydrophthalazine-1,4 dione) is the most popular of presump-tive blood tests. The oxidation of Luminol results in chemilumi-nescence. In the presence of an oxidant, transition metal cations catalyze the oxidation of Luminol. Hemoglobin, which transports Fe+ ions and has an activity re-sembling that of peroxidase, de-monstrates this catalyzer effect.
Thus, blood catalyzes the oxidati-on reactioxidati-on between Luminol and H2O2. As a result of the oxidation, the exitated form of Luminol pro-duces a blue-coloured lumines-cence (1, 2).
It has been reported that Lumi-nol has the highest sensitivity and specificity compared to the other
blood stain tests (3, 4) and does not have a negative effect on PCR steps (1, 4). Another advantage of Luminol is that its toxic or carci-nogenic effect could not be de-monstrated until today (5). The use of calf spleens as the bi-ological targets was based on the presumption that the spleen is a tissue containing a vast amount of blood. Additionally, the study of Quickenden and Cooper showed that there is no difference bet-ween human hemoglobin and calf hemoglobin in terms of Lumino emission (6).
MATERIAL AND
METHOD
A barrel filled with 10 cm sand and 90 cm cotton above was used for the test shots. Then 50 test shots were fired with a 7.65 mm semi-automatic pistol. In 20 of
However, if the bullet leaves the body, it is difficult to solve a crime.
The ambiguities may still persist even if a suspected weapon or even
a bullet or cartridge case is found. Especially if multiple suspects
and suspected weapons are present, the doubts can not be ruled
out. In such cases, the bullets found in the crime scene should be
examined for biological residues. The determination of residues
on the bullet, which belong to the wounded person, constitutes an
important evidence.
these shots, calf spleens purc-hased from the market in a nylon bag were put in a cardboard box and placed on the cotton as tar-gets. After the shots, the bullets obtained were examined for sple-en residues. To this sple-end, a com-mercial kit named Bluestar was used. The kit including Luminol was prepared in accordance with the prospectus. Distilled water purchased from the market was used in the solution, which was
prepared in the area where the shots were fired, whereas deio-nized bidistilled water was used in the spray, which was prepared a few days later. The prepared spray was applied on the bullets obtained from the test shots and the bullets were examined for blood stains.
The bullets obtained after the shots were coded and lined up on a tray. At that moment, it was not known which bullets had hit the spleens. The bullets that would show blue luminescence in the dark room after the Luminol app-lication would be considered as those that had hit the target.
RESULTS
When the Luminol test was appli-ed for the first time, no lumines-cence was obtained. Moreover, luminescence was not obtained even when Luminol was applied to the blood stains. Consequently, the rest of the experiment was postponed. The test was repeated two days after the first attempt with the new Luminol solution and this time luminescence was
observed both on the bullets that had hit the mark and those that had not. As a result, the idea of attempting to guess which bul-lets had hit the mark and which had not, was abandoned. The lu-minescence obtained was not so strong and required perfect dark room conditions. The lumines-cence observed in some bullets was more prominent compared to that observed in the others. However, after comparing the numbers assigned to these bul-lets with the previously entered records, it was understood that some of those bullets had hit the mark and some had not.
DISCUSSION
As the first attempt with Luminol was unsuccessful, the reasons behind the failure were investi-gated. Because no results were obtained even when Luminol was applied on the blood stains. It was hypothesized that one of the rea-sons for the failure could be the distilled water purchased from the market. The product was sold in markets to be used in cars and
serious sanctions aimed to pre-vent the sale of products that are below the standards are not pre-sent. Impurity indicates that the water contains ions. These ions might have begun to support the reaction between Luminol and H2O2 right from the start of the solution’s preparation and the re-action might have been completed at the time of application. As for the second experiment conducted a few days after the unsuccessful attempt, and from which positive results were obtained, deionized bidistilled water was used in it. Another reason for the failure of the first attempt could be that the room where the application was carried out was not dark enough. The test shots were fired in a
The bullets obtained after the shots were coded and lined up on a
tray. At that moment, it was not known which bullets had hit the
spleens. The bullets that would show blue luminescence in the dark
room after the Luminol application would be considered as those
that had hit the target.
garden hut far away from the city. After the curtains on the windows of the hut were drawn, Luminol was used inside the cupboard in the kitchen. Certainly, the rese-archer was outside the cupboard and the door of the cupboard was open. A darker environment was required to watch the lumines-cence of Luminol.
It was also observed in the experi-ment carried out a few days later
with the newly prepared solution that the luminescence was not as strong as anticipated by the researcher. This time, an almost completely dark room was prepa-red. The hallway behind the door was dusk. Some light was leaking from the dusk hallway, through the space under the door. Howe-ver, the leaking light could illumi-nate the room only as much as a 2-inch LCD monitor. Under those circumstances, blue luminescen-ce could be observed when Lu-minol was applied on the bullets. However, it was not possible to watch the luminescence when the door was opened even slightly. Moreover, the luminescence was weakening just 10-15 seconds af-ter the application of the spray. A pleasing development was that
a luminescence nearly as strong as the first one could be obtained when the spray was used for the second time.
Unfortunately, the result of the Luminol test was positive for all bullets. This might have resulted from one or more reasons. The metal of the bullets or the gun-powder residues on the bullets might have produced a similar chemiluminescence resembling
that produced by hemoglobin. Some of the glove powder used during the collection of the bul-lets might have been left on them. This might be another reason of the false positivity. Finally, blood contamination might have occur-red in spite of the great attention paid. Although a different glove was used, contamination between the bullets that had hit the sple-ens and those that had not might have occurred.
Comprehensive studies investiga-ting the substances that produ-ce a chemiluminesprodu-cenprodu-ce similar to that produced by hemoglobin have been conducted (7, 8). In those studies, the interference of numerous industrial, domestic and environmental substances
has been analyzed. However, the substances that might have ca-used false positivity in our study have not been studied in those studies. The metal of the bullet, the gunpowder residues on the bullet and the glove powder are the substances, which are the probable sources of false positi-vity in our study. No studies in-vestigating the interaction of the-se substances with Luminol could be found in the literature.
Our study was carried out without the equipment capable of measu-ring the intensity and spectrum of Luminol emission. However, the study of Quickenden and Co-oper showed that the emission of the substances that may cause interference with Luminol may be different from that of hemog-lobin and it is possible to detect this difference (6). To illustrate, the emission peak of hemoglobin is 455 nm whereas the emission peak of hypochloride is 430 nm. Sodium hypochloride is a subs-tance that is present in the whi-teners used for the crime scene cleanup and it causes interferen-ce with Luminol.
It was thought that the failure in photographing the observed
It was also observed in the experiment carried out a few days later
with the newly prepared solution that the luminescence was not
as strong as anticipated by the researcher. This time, an almost
completely dark room was prepared. The hallway behind the door
was dusk.
luminescences originated from the amateur camera. At amate-ur level, quite successful images can be acquired with the camera used in the study. Besides, almost perfect images can be obtained under the moonlight. However, the desired results could not be obtained with the fully automatic device in the dark room requiring long-term exposure.
Many experiments were conduc-ted during the present study to obtain good-quality images with Luminol. During these experi-ments an interesting event oc-curred. As Luminol was applied to a stain that was formed by smearing minced calf meat on a piece of paper, luminescence was obtained not right on the sta-in but around it, like an aureole. The dissolvable part of the stain should have diffused on the paper during the period before Luminol application. Probably, this part of the stain, which spread out in the
tissue of the paper, triggered the reaction between Luminol and H2O2 more. It is also probable that the blue luminescence could be perceived less on the dark-coloured stain. It is known that results can be obtained by the Lu-minol test in spite of an attempt by the criminal to clean up the blood stains (9). It should be bor-ne in mind that on a surface such as a faience tile where the liquid, unlike paper, can not be absor-bed, a dark-colored blood stain may attract less attention or even can not be seen at all compared to blood stains at trace amount. Although the desired results were not obtained by the Luminol test, we still uphold our opinion. The bullets found in the crime scene should be examined for biological residues or blood stains. Because the presence of biological residue on a bullet and the match betwe-en the DNA profile of the woun-ded person and the DNA obtained
from the residue show that that particular person was wounded by that particular bullet. In many instances, this constitutes the strongest evidence. On the other hand, the absence of biological residue on a bullet shows that that particular bullet did not cau-se the injury. Thus, the examina-tion of the bullets obtained from the crime scene for biological residues should become a part of the routine investigation process. The experiment should be repe-ated with equipment capable of measuring the intensity and the spectrum of the emission or with other presumptive tests.
Acknowledgements: Thanks to
Ali Arısoy, my father, who cont-ributed so much to the experi-ments by firing the test shots and to Deniz Başkaya for the English translation of the study.
REFERENCES
1. Blum LJ, Esperança P, Rocquefelte S. A new high-performance reagent and proce-dure for latent bloodstain detection based on luminol chemiluminescence. Can Soc Forensic Sci J, 2006; 39 (3): 81-100
2. Ahlquist DA, Schwartz S, Ahlquist DA, Schwartz S. Use of leuco-dyes in the quantitative colorimetric microdetermina-tion of hemoglobin and other heme com-pounds. Clin Chem, 1975; 21(3):362-9.
3. Webb JL, Creamer JI, Quickenden TI. A comparison of the presumptive Luminol test for blood with four non-chemilumi-nescent forensic techniques. Lumines-cence, 2006; 21(4):214-20.
4. Tobe SS, Watson N, Daéid NN.
Evalu-ation of six presumptive tests for blood, their specificity, sensitivity, and effect on high molecular-weight DNA. J Forensic Sci, 2007; 52(1):102-9.
5. Sanders JM, Chen LJ, Burka LT, Mat-thews HB. Metabolism and disposition of Luminol in the rat. Xenobiotica. 2000; 30(3):263-72.
6. Quickenden TI, Cooper PD. Increasing the specificity of the forensic Luminol test for blood. Luminescence, 2001; 16(3):251-3.
7. Quickenden TI, Creamer JI. A study of common interferences with the forensic Luminol test for blood. Luminescence, 2001; 16(4):295-8.
8. Creamer JI, Quickenden TI, Apanah MV, Kerr KA, Robertson P. A comprehensive experimental study of industrial, domestic and environmental interferences with the forensic Luminol test for blood. Lumines-cence, 2003; 18(4):193-8.
9. Creamer JI, Quickenden TI, Crichton LB, Robertson P, Ruhayel RA. Attempted cleaning of bloodstains and its effect on the forensic luminol test. Luminescence, 2006; 20(6):411-3
İletişim Adresi:
Prof. Dr. Yücel Arısoy Dokuz Eylül Üniversitesi Tıp Fakültesi Adli Tıp AD 35340 Bayçova, İzmir
