Blood Processing Question

[ekuadam]

Just out of curiosity, at your labs, if you get an item that has possible blood on it, but no visible ridges, do you do any blood processing like Amido Black or Acid Yellow? Or do you all only use blood processing reagents if you see ridges in blood?

[Ernie Hamm]

You are in a '"risk/reward" situation. Amido Black is very sensitive to blood matter and could react to 'unseen' blood substance in latent prints, but could be viewed as a destructive technique to other latent developing techniques. There are two 'ancient' articles that address sequencing of techniques involving blood and perhaps can provide some guidance:

Preprocessing with Cyanoacrylate Ester Fuming for Fingerprint Impressions in Blood, Mary M. McCarthy and David L. Grieve, Journal of Forensic Identification, 39:1, (1989), Comment: Effect on CA processing prior to application of stain agents for blood

Variation to Coomassie Blue Blood Print Enhancement Technique, Robert Whritenour, Identification News, 36:11 (1986), Comment: Process plastic first with CA and then use Coomassie Blue BLOOD STECH CYAN

Blood matter can be very hardy on certain surfaces and could survive powder processing and still react to Amido Black.

[Ernie Hamm]

Back Again. Cobwebs in the mind parted enough to remind me of another approach.

I once had some blood contaminated footwear tracks on a linoleum floor and, while suitable for comparison, there was always an effort to enhance the details. There were standard photographs taken before any enhancement, but this was followed by ultraviolet illumination as a non-destructive technique before applying blood stain dye. The results were somewhat surprising as the UV illumination detected unseen areas of the blood track made by the outsole. This indicated that the blood manner was sensitive to the UV illumination and revealed 'unseen' blood transfer. You could use UV illumination on the chance that could confirm blood transfer before you proceed with any enhancement techniques.

Back to the tar pit.

[ekuadam]

Thanks Ernie!!
We have access to LCV, Amido Black and Acid Yellow in our lab. Reason I was asking is because if I get an item (lets say a knife) that just has blood on the blade, but I see no ridges at all. Its just blood spots or smears. There would be no reason to use a blood reagent because they are just stains right? Now if I saw some ridge detail, I would use whatever blood reagent I found best, but if there are no ridges wouldn't it be a waste of time/resources to process with a blood reagent?

[Ernie Hamm]

Adam,

Again, the dilemma of risk vs. reward. However, be sure you have exhausted your options before proceeding. If there is some indication, or belief, that a blood print could be present, you should proceed with any viable techniques, stopping short of destroying the print. There is the sequencing of techniques to better the outcome. I mentioned the alternate light source (UV) because it is non-destructive and I have seen reactions that were not visible ‘in situ’. It was beneficial in that particular instance, but may not be in others. However, alternate light sources are non-destructive and not time consuming in their application.

I had a case of an assault when the victim was tied with white surgical tape which she removed after the incident and threw the tape in a toilet bowl, where it was recovered. There was the issue with water contamination and the surface on one side was surgical adhesive and the other with a cloth like surface, also contaminated. The evidence was air dried and then I needed to think about a method of examination. I fell back on the early iodine fuming method using the assembled fuming tube and breath technique, a non-destructive method of latent development. I was successful in developing a beautiful, fully rolled thumb print in the adhesive that was photographed during development and subsequently identified to a subject.

I once had a see through glass picture in my office of a wizard waving the wand with the message, “Only those that see the invisible can do the impossible”.

Good luck in your endeavor.

Ernie