Tuesday, April 27, 2010
An Interesting Fingerprinting Technique
I'm not sure if there are any fingerprint techs who read this blog, but for those who work in law enforcement or related fields, I wanted to pass along an interesting technique for fingerprinting hands that have decomposed beyond the point of being able to print them in the normal fashion. It is an unusual technique that is virtually unknown in the US (it was passed along to me via video from a forensics team in South Africa). So you have a hand which would normally be considered too decomposed to pull prints from. Simply pour boiling water over the fingers and palm. You will see the muscles contract and the fingers rise up. Dry the fingers and palm, dust the hand like you are dusting for latent prints, take some white fingerprint tape and proceed to print the fingers. You now have mirror images of the fingerprints on the tape which I am told are quite accurate and useful for identification. Interesting.
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Not interesting, not the latest science. Stick to what you know.
ReplyDeleteI'm not a fingerprint analyst, but do work in law enforcement. It's morbid, but when an unidentified deceased person is found, crime scene technicians have been known to remove a hand in order to transport it to a forensic lab for processing. All sorts of environmental factors may come into play that cause the fingerprint ridge pattern to become distorted - aridity causes the skin to dehydrate, submersion in water causes the tissues to bloat, and the normal processes of decay and/or predation can result in missing portions of the 10-print. Techniques such as re-hydration, de-hydration, and removal of the skin from the underlying hand structure in order for the tech to "glove up" and ink roll to obtain the fingerprint patterns are all used in order to successfully capture an image of the patterns.
ReplyDeleteWhy remove the hand only? Unless the circumstances are extremely obvious, unattended deaths are usually presumed to be homicides until investigation reveals otherwise. The remains are considered part of the scene and must remain there until the crime scene personnel have processed everything and collected anything of evidentiary value. As a decaying body is succumbing to natural processes that make identification more difficult as time progresses, sometimes that single hand is removed so that the fingerprints can be collected and run through the national fingerprint database (AFIS)- the quickest and most conclusive means of making a definitive identification that is at the disposal of law enforcement. Forensics are a fascinating application of scientific techniques.
I'm not a fingerprint analyst either. I do, however, like to share things that I learn in the hopes that it will be useful to others. I find forensics fairly fascinating but am by no means an expert...just an interested observer.
ReplyDeleteVery interesting, and likely one technique of many that can be used by forensic scientists. Thank you for sharing.
ReplyDeleteI too find forensic's interesting.As far as not being the latest science,sometimes old proven techniques are better than the latest.
ReplyDeleteChina
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