recovering bloody fingerprints from skin red is a well-known blood-staining agent [7]. experiments...

Journal of Forensic Identification65 (5), 2015 \ 813

1 Hungarian Institute for Forensic Sciences, Department of Crime Scene Investigation

2 Hungarian Institute for Forensic Sciences, Department of Forensic Medicine

Received December 3, 2014; accepted January 28, 2015

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 f ingerprints from cadaver skin. Several tests with varying quantities of blood on a thumb and f ingers 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 f ive planted prints being identif iable.

IntroductionThis paper focuses on the development of blood-stained

fingerprints on human skin, both cadaver and living, by apply-ing 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 applica-tion 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].

Journal of Forensic Identification814 / 65 (5), 2015

Leucocrystal violet (BVDA Cat. No. B-88600, Netherlands) is a cationic triarylmethane dye that has an affinity for both cellu-losic 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 inger-prints and footprints made in blood. Because of the water-based solution of the Hungarian red, it is not considered to be a hazard-ous 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 ExperimentBefore using on human cadaver skin, we conducted a prelimi-

nary 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 BlackNo f ixat ive was used because the staining solut ion is

a methanol-based amido black dilut ion, which does not require a f ixative. 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 VioletLeucocrystal violet comprises a separately packed water-

based LCV solution and a water-based hydrogen peroxide dilution. For the experiment, we mixed the two solutions in


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 dissec-tion table.

Application of Hungarian RedBefore dyeing with Hungarian red, the bloody prints needed

to be fixed. We used 2% 5-sulfosalicic acid diluted in distilled water. Despite the inst ructions of BVDA, 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 f ixative 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 preliminary experiment yielded the expected result: all three developers worked equally well on the smear slides (Figures1–3),andallf ingerprintsweresufficienttoidentifya person.

Figure 1Amido black-treated print on smear slide.


Figure 2LCV-treated print on smear slide.

Figure 3Hungarian red-treated print on smear slide.


First ExperimentFollowing 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 deter-mined 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, ontheskin,thebloodstainmadenovisiblemark–itwasalmostinvisible.

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 f ingerprints, with no friction ridge details. Although the f ingerprint pattern 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 experi-ments.

The AB delivered good results; the developed f inger-prints were of good enough quality for personal identification (Figure 5). AB could be removed only with the ethanol-contain-ing 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 finger-prints 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 consid-ered 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.


Figure 4LCV-treated print on cadaver skin.

Figure 5Amido black-treated print on cadaver skin.


Second ExperimentOur 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 f ingers (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 cadav-er’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 f ingers 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 printswaspracticallyinvisible(Figures7–10).

Figure 6Hungarian red-treated print on cadaver skin.


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

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


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

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


After depositing the prints, the body was stored in the refrig-eration chamber of the mortuary. Seventy-two hours later, we attempted to develop the bloody prints. Although the tempera-ture 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 suffi-cient 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

refr igerated 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.


Sex Age(years) Race Comments about the Body AS* AK* AN*

1 Male 57 Edema; reduced elasticity of skin 0 0 92 Male 54 Hairy surface; had weak results 2 2 53 Male 60 Reduced elasticity of skin 2 1 64 Male 64 2 4 35 Male 74 5 3 16 Male 41 Lower limbs were shaved 3 2 47 Female 82 2 4 38 Female 37 4 3 2

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

Table 1Results of the third experiment.

Fourth ExperimentDuring 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 approxi-mately 60 minutes, the f ixing and dyeing method was used. Running tap water was used for rinsing off the surplus 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.


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

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


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

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


DiscussionBased on our observations, there was no significant connec-

tion 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, f ine hair had no effect on the print.

ConclusionOur 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 f ingers 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 refrig-erated 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 long-lasting coloring of the body.

AcknowledgmentThe authors would like to thank the University of Pécs,

Faculty of Medicine. For further information, please contact:

David PetreteiHungarian Institute for Forensic Sciences1087 Budapest, Mosonyi u. 5., Hungarypetreteid@orf k.police.hu


References1. Warrick, P. Identif ication of Blood Prints on Fabric Using

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2. 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.

3. LaForte, M. F. Fingerprints on Human Skin: The Libby Miller Case. June 4, 2012. http://www.crimescenejournal.com/con-tent.php?id=0004 (Accessed July 21, 2014).

4. BVDA. Latent Fingerprint Investigation: Staining of Traces in Blood. http://www.bvda.com/EN/sect1/en_1_11a.html (Accessed July 21, 2014).

5. Bodziak, W. J. The Use Of Leuco Crystal Violet To Enhance ShoePrintsInBlood.May8–11,1995.http://www.bvda.com/EN/prdctinf/LCV_Bodziak.html (Accessed July 21, 2014).

6. BVDA. Product Informat ion: How to Use Hungar ian Red. http://www.bvda.com/EN/prdctinf/en_hu_red.html (Accessed July 21, 2014).

7. Theeuwen, A. B. E.; van Barneveld, S.; Drok, 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.

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recovering bloody fingerprints from skin red is a well-known blood-staining agent [7]. experiments...

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