Eileen Schuh

Entries in crime scene (1)

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.