Canadian forensic scientist introduces slime-based fingerprint detection to enhance visibility

A forensic science graduate of the University of Toronto Mississauga has developed an innovative ‘slime’-based fingerprint technique to improve fingerprint visibility in investigations, the institution announced.

Inspired by American forensic investigator Caleb Foster, Leanne Byrne decided to test the technique, resulting in an independent study conducted together with U of T forensic identification instructor Wade Knapp and lab technician Agata Gapinksa-Serwin.

Byrne focused on crystal violet and amido black, two reagent compounds used in investigations. Traditionally, to improve fingerprint visibility, investigators use liquid chemical sprays or bath solutions.

“Reagent agents in the slime reacts with the fingerprint, producing a stain that enhances the detail so we can photograph it,” Byrne told the university. “My method proposes an inexpensive technique that uses borax mixed with glue as the baseline compound. With this method, investigators can press the slime on the fingerprint, wait a couple of seconds and lift it up. If it hasn’t stained sufficiently, it can be reapplied as needed.”

The slime was tested against multiple surfaces, such as black electrical tape, beige and clear packing tapes, silver duct tape and painted wood tiles, as well as against aging fingerprints and bloody versus non-bloody.

Byrne is pleased with her results, saying the slime on black electrical tape and beige packing tapes provided the best visibility augmentation.

“Fingerprints can change over time, depending on the environment and variables like temperature and humidity,” she said. “We can’t always tell the age of the fingerprint, so we want to make sure that a technique is going to work consistently regardless of the age.”

Byrne discussed her results in a virtual conference of the Canadian Society of Forensic Sciences. The study was included in the June 2020 issue of forensic journal Identification Canada.

Article Topics

biometric identification  |  biometrics  |  biometrics research  |  criminal ID  |  fingerprint biometrics  |  forensics  |  law enforcement