Wednesday
Oct172012
...that fingerprints...
Wednesday, October 17, 2012 at 12:36AM
I attended a presentation by my local RCMP Forensic Ident officer this evening and learned things about fingerprints, footprints, DNA and other crime scene clues. Here's a few fun facts I picked up:
- fingerprints are particularly easy to lift from potato chip bags because
- it is grease and oil one gets from touching body parts, such as face or hair (or from chips you eat), clinging to the fingers that creates fingerprints
- this grease sticks to the fingers because we have many sweat pores on our fingers. We can see these if we look closely. They look like tiny holes.
- fingerprints can be easily lifted from paper. It is heated and then treated and voila! Prints appear!
- put superglue in a heating chamber with a plastic bag and the glue will become gaseous and cling to the oily finger prints on the bag, making them visible. This is a valuable technique as many illicit drugs are stored, traded, transferred in ordinary plastic Ziploc bags.
- a technique has yet to be discovered for lifting prints from rocks...which means if a rock smashes through your window, it likely won't be useful in the ensuing vandalism investigation.
- Despite digitalization of fingerprints, computerized transmission of fingerprints, and the national fingerprint data base Automated Fingerprint Identification System (AFIS), it still takes a human to do the ultimate match up. The computer can only narrow it down to a dozen or so similar prints. It is a labour-intensive job and truly does still involve lab techs staring at prints through magnifying glasses.
- A partial print on a revolver leads investigators to suspect young Katrina Buckhold played a part in a horrific gang slaying in FATAL ERROR, my new crime novel. Sequel to The Traz.
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tagged AFIS, FATAL ERROR, The Traz, crime scene, fingerprints, forensic ident