Technical Note

Recovering Bloody Fingerprints from Skin

David Petretei 1 Miklos Angyal 2 Abstract: Well-known processes for developing blood prints (i.e., amido black, leucocrystal violet, and Hungarian red) were tested to recover bloody fingerprints from cadaver skin. Several tests with varying quantities of blood on a thumb and fingers were tested to determine the most effective process. The process using Hungarian red proved to be the most successful and was then tested on living human skin, resulting in two of the five planted prints being identifiable.

Introduction This paper focuses on the development of blood-stained fingerprints on human skin, both cadaver and living, by applying different developers. Three developers were selected for the experiments: (1) amido black (AB), (2) leucocrystal violet (LCV), and (3) Hungarian red (also known as acid fuchsin). Amido black is a chemical dye solution that binds to protein molecules in blood and yields a dark blue color [1]. The application of the AB method on human skin has been described in the scientific literature for more than a decade [2]. Field application has been reported for more than two decades [3]. The amido black kit (BVDA Cat. No. B-89501, Netherlands) that was used during the experiment was methanol based and had three stages: staining, rinse 1, and rinse 2 [4]. Hungarian Institute for Forensic Sciences, Department of Crime Scene Investigation 2 Hungarian Institute for Forensic Sciences, Department of Forensic Medicine 1

Received December 3, 2014; accepted January 28, 2015 Journal of Forensic Identification 65 (5), 2015 \ 813

Leucocrystal violet (BVDA Cat. No. B-88600, Netherlands) is a cationic triarylmethane dye that has an affinity for both cellulosic and proteinaceous materials. LCV is often called gentian violet. LCV is the completely reduced form of crystal violet and is therefore colorless. When LCV and hydrogen peroxide come into contact with the hemoglobin in blood, a catalytic reaction occurs and the solution turns to a purple-violet color [5]. Hungarian red (BVDA, Netherlands) is a dye solution in a water-acetic acid mixture that is used for staining f ingerprints and footprints made in blood. Because of the water-based solution of the Hungarian red, it is not considered to be a hazardous material and may not affect the toxicology results. Prints in blood are colored red after treatment with Hungarian red [6]. Hungarian red is a well-known blood-staining agent [7]. Experiments – Blood Preliminary Experiment Before using on human cadaver skin, we conducted a preliminar y experiment with the three aforementioned methods to verify the suitability of each method. Author 2 performed a venipuncture on author 1 and partially filled a small petri dish. Author 1 put his thumb into the untreated blood for 1 second, and after 1 to 3 seconds of air-drying, author 1 slightly rubbed his thumb with his forefinger. He then placed bloody thumb prints on the glass surfaces (smear slides), holding for 1 second, using moderate pressure. The blood was replenished on the thumb between each impression. Application of Amido Black No f ixative was used because the st aining solution is a met ha nol-based a m ido black d ilut ion, wh ich does not require a fixative. We used the methanol-acetic acid solution (“rinse 1”) for the first rinsing. After 10 to 15 seconds, the 5% aqueous acetic acid (“rinse 2”) was used for the second rinsing. All three components were sprayed. No additional water or other solvent was used. Application of Leucocrystal Violet Leucocrystal violet comprises a separately packed waterbased LCV solution and a water-based hydrogen peroxide dilution. For the experiment, we mixed the two solutions in Journal of Forensic Identification 814 / 65 (5), 2015

a mixing ratio of 1:4, 10 minutes before using. LCV does not require any fixative. After 10 to 20 seconds of spraying using a hand-held sprayer, we had to wash the surface off with tap water, otherwise the entire surface would have become purple. Tap water was used directly from the built-in hose of the dissection table. Application of Hungarian Red Before dyeing with Hungarian red, the bloody prints needed to be fixed. We used 2% 5-sulfosalicic acid diluted in distilled water. Despite the inst r uctions of BV DA, we sprayed the fixative directly onto the prints and did not use any absorbent paper to cover them. Spraying was performed while keeping a relative distance from the surface to avoid the spray washing the prints off. (BVDA’s instructions advise using the absorbent paper to avoid the fixative washing the details off. But we used the fixative with careful attention; the prints were preserved. Covering the untreated prints seemed to be risky.) After 20 to 30 seconds, we used the staining solution, and after another 10 to 20 seconds, we rinsed the slides with tap water. Both the fixative and the staining solution were sprayed; tap water was used directly from the built-in hose of the dissection table. The preliminar y experiment yielded the expected result: all three developers worked equally well on the smear slides (Figures 1–3), and all fingerprints were sufficient to identify a person.

Figure 1 Amido black-treated print on smear slide. Journal of Forensic Identification 65 (5), 2015 \ 815

Figure 2 LCV-treated print on smear slide.

Figure 3 Hungarian red-treated print on smear slide.

Journal of Forensic Identification 816 / 65 (5), 2015

First Experiment Following the preliminary test, we conducted an experiment on a fresh cadaver (an elderly female). The cadaver, having a smooth skin, had not been previously refrigerated, and we determined that no moisture would appear on the skin that could affect the success of our experiment. Author 2 performed a venipuncture on author 1. Author 1 put his thumb into the untreated blood for 1 second, and after 1 to 3 seconds of air-drying, author 1 slightly rubbed his thumb with his forefinger. He then placed thumb prints on the skin, holding for 1 second, with moderate pressure. We observed that, on the skin, the bloodstain made no visible mark– it was almost invisible. After 15 minutes, all three development methods were carried out one after another on the cadaver, in full conformity with how they had been performed earlier on the smear slides in the preliminary experiment. The LVC produced only faint fingerprints, with no friction ridge details. Although the f inger print patter n verif ied the touch itself, it was not sufficient even for exclusion purposes (Figure 4). The LCV was removed from the skin with tap water and soft wiping with paper towels. Because the LCV failed to produce usable prints, it was not used in the subsequent experiments. T he A B delivered good results; the developed f i ngerprints were of good enough quality for personal identification (Figure 5). AB could be removed only with the ethanol-containing rinse solution and soft wiping with paper towels. Although this cleansing process may render the skin surface clean, the presence of alcohol in the AB rinse solution may inf luence toxicology results [8]. The Hungarian red gave good results; the developed fingerprints were of good enough quality for identification (Figure 6). The Hungarian red was removed from the skin with tap water and soft wiping with paper towels. Hungarian red is not considered to be a hazardous material; it is a water-based solution with only some acetic acid component. Hungarian red contains no methanol, hence would not inf luence any toxicology results. Furthermore, it can easily be removed from the skin.

Journal of Forensic Identification 65 (5), 2015 \ 817

Figure 4 LCV-treated print on cadaver skin.

Figure 5 Amido black-treated print on cadaver skin.

Journal of Forensic Identification 818 / 65 (5), 2015

Figure 6 Hungarian red-treated print on cadaver skin.

Second Experiment Our second examination exclusively focused on Hungarian red because amido black is already widely used in the f ield worldwide and is covered in the literature. Also, we wished to find a proper alternative to methanol-based amido black, because of its possible interference with toxicology [8] results. At this time, our aim was to test the method on a body that had been stored for a few days in the mortuary. Author 2 performed a venipuncture on author 1. Author 1 applied some untreated fresh blood directly from the syringe to his four fingers (excluded thumb). After 1 to 3 seconds of air-drying, author 1 slightly rubbed his fingers with his thumb and then placed the four fingerprints of the four fingers on the skin, holding for 1 second, with moderate pressure. Sixteen prints were deposited in groups of four on the cadaver’s (elderly female) lower limbs (shins). The four groups of prints were deposited with fingers that had been smeared with different amounts of blood. The first group of prints was placed with fingers soaking in blood; the second group was deposited with fingers covered in a considerable amount of blood. Less blood was used to make the third group of prints. Only a very thin layer of blood covered the fingers that placed the last four prints. It is important to note that the prints in the third group were barely visible to the human eye, and the fourth group of prints was practically invisible (Figures 7–10). Journal of Forensic Identification 65 (5), 2015 \ 819

Figure 7 First group of bloody fingerprints on cadaver skin before processing.

Figure 8 Second group of bloody fingerprints on cadaver skin before processing.

Journal of Forensic Identification 820 / 65 (5), 2015

Figure 9 Third group of bloody fingerprints on cadaver skin before processing.

Figure 10 Fourth group of bloody fingerprints cadaver skin before processing.

Journal of Forensic Identification 65 (5), 2015 \ 821

After depositing the prints, the body was stored in the refrigeration chamber of the mortuary. Seventy-two hours later, we attempted to develop the bloody prints. Although the temperature of the skin was 5 °C and slightly moist, the visibility of the prints did not show any change. The method was the same as in the preliminary experiment: surface fixation with the 2% 5-sulfosalicic acid solution, then dyeing with the Hungarian red. We used tap water to remove the surplus of the dye. Fifteen of the 16 prints proved to be visible. All 15 prints were sufficient to verify that prints were present. Two of the four prints of the first group of prints did not have visible friction ridges or minutiae. One had visible friction ridges with a few minutiae, but they were not sufficient for determining the pattern. One of the prints had 12 minutiae, making it sufficient to identify a person. (In Hungary, 10 minutiae points are required as a minimum for the identification of persons based on fingerprints.) (Figure 11). In the second group of prints, there were two prints with four and five minutiae, but they were not sufficient for determining the pattern. The remaining two prints had four and five minutiae as well; however, in this case, we could determine the pattern (plain whorl), enabling us to exclude certain persons (Figure 12). Three prints in the third group were of good quality. The fourth one was not visible, giving the impression that the amount of dye that we used had not been enough, because the tap water washed off the dye and left no residual traces. One of the other three had six minutiae and a visible pattern (plain whorl) as well. Two of the four prints in the third group had outstanding quality, with clean and sharp friction ridge structure (Figure 13). The fourth group of prints contained three prints without any visible pattern or friction ridge. Although the fourth one had a visible pattern (plain whorl), it showed only six minutiae, rendering it insufficient for identification (Figure 14). Third Experiment In the third experiment, we tested Hungarian red on eight refrigerated cadavers and the results are listed in Table 1. Methods of print deposition and development were the same as for experiment 2. Nine prints were deposited on each body. All of the deposited prints were successfully developed by dyeing. Journal of Forensic Identification 822 / 65 (5), 2015

Sex

Age (years)

Comments about the Body

AS*

AK*

AN*

1

Male

57

Edema; reduced elasticity of skin

0

0

9

2

Male

54

Hairy surface; had weak results

2

2

5

3

Male

60

Reduced elasticity of skin

2

1

6

4

Male

64

2

4

3

5

Male

74

5

3

1

6

Male

41

3

2

4

7

Female

82

2

4

3

8

Female

37

4

3

2

Race

Lower limbs were shaved

AS = identifiable AK = recognizable pattern and enough minutiae to exclude AN = no pattern or enough minutiae to identify or exclude * Abbreviations are according to regular Hungarian terminology.

Table 1 Results of the third experiment.

Fourth Experiment During the fourth experiment, we tested Hungarian red on a living person. Venipuncture was the same as before. Untreated fresh blood was applied with a syringe to the fingers. Six prints were deposited to the shaved forearm of author 1. After approximately 60 minutes, the f ixing and dyeing method was used. Running tap water was used for rinsing off the sur plus dye. After the dyeing, five prints were developed. Three prints had no visible friction ridge details or recognizable pattern, but two prints had enough minutiae to be identifiable. Neither the fixing nor the dyeing caused any irritation or pain on the skin. After the experiment, the stain could be completely removed by running tap water and common soap.

Journal of Forensic Identification 65 (5), 2015 \ 823

Figure 11 Prints from the first group after treatment with Hungarian Red.

Figure 12 Prints from the second after treatment with Hungarian Red.

Journal of Forensic Identification 824 / 65 (5), 2015

Figure 13 Print from the third group after treatment with Hungarian Red.

Figure 14 Print from the fourth group after treatment with Hungarian Red.

Journal of Forensic Identification 65 (5), 2015 \ 825

Discussion Based on our observations, there was no significant connection between the quality of prints and the age of the cadaver. The main factor that inf luenced the ability to achieve good results was the actual state and condition of skin. Dry skin, reduced skin elasticity, exfoliation, or extent of edema on the affected area made the developed prints considerably blurred. On some parts, where only thin, soft tissue covered long bones (e.g., the shins), obtaining prints was more diff icult. Thus, skin from different areas of the same body, only 10 cm distance from each other, could be vastly different and could affect the abilty to produce quality prints. The thickness of hair also inf luenced print development. Thick hair on the skin collected the blood and later collected the dye, causing “clumping”. The print became blurry, with a lack of ridge details. Soft, fine hair had no effect on the print. Conclusion Our experiments show that Hungarian red can be employed with success to develop bloody prints on bodies. Prints left by blood-soaked fingers and prints of fingers barely coated in blood might equally be suitable to verify touch, show pattern, or even identify a person. Moderately blood-stained prints yielded slightly better results. Hungarian red can be employed on fresh cadavers and refrigerated cadavers. Age and gender did not have an effect, but thick hair and skin problems did. Hungarian red can be employed even on living human skin without the risk of poisoning or longlasting coloring of the body. Acknowledgment The authors would like to thank the University of Pécs, Faculty of Medicine. For further information, please contact: David Petretei Hungarian Institute for Forensic Sciences 1087 Budapest, Mosonyi u. 5., Hungary petreteid@orf k.police.hu

Journal of Forensic Identification 826 / 65 (5), 2015

References 1. 2. 3. 4. 5. 6. 7.

8.

Warrick, P. Identification of Blood Prints on Fabric Using Amido Black and Digital Enhancement. J. For. Ident. 2000, 50 (1), 20 –32. Lawley, R. Application of Amido Black Mixture for the Development of Blood-based Fingerprints on Human Skin. J. For. Ident. 2003, 53 (4), 404– 408. LaForte, M. F. Fingerprints on Human Skin: The Libby Miller Case. June 4, 2012. http://www.crimescenejournal.com/content.php?id=0004 (Accessed July 21, 2014). BVDA. Latent Fingerprint Investigation: Staining of Traces in Blood. http://www.bvda.com/EN/sect1/en_1_11a.html (Accessed July 21, 2014). Bodziak, W. J. The Use Of Leuco Crystal Violet To Enhance Shoe Prints In Blood. May 8–11, 1995. http://www.bvda.com/ EN/prdctinf/LCV_Bodziak.html (Accessed July 21, 2014). BV DA. P roduct I n for mat ion: How to Use Hu nga r ia n Red. http://www.bvda.com/EN/prdctinf/en_hu_red.html (Accessed July 21, 2014). T heeuwen, A. B. E.; va n Ba r neveld , S.; D rok , J. W.; Keereweer, I.; Limborgh, J. C. M.; Naber, W. M.; Velders, T. Enhancement of Footwear Impressions in Blood. For. Sci. Int. 1998, 95 (2), 133–151. Beaudoin, A. Comparison of Ortho-Tolidine and Amido Black for Development of Blood-Based Fingerprints on Skin. J. For. Ident. 2012, 62 (6), 588–601.

Journal of Forensic Identification 65 (5), 2015 \ 827