KGUN 9NewsLocal News


How Tucson police use fingerprint technology to crack cases

An inside look at the Tucson Police crime lab
Posted at 12:53 PM, Nov 10, 2019
and last updated 2019-11-10 15:03:40-05

TUCSON, Ariz. — When Tucson police investigate crimes like robberies, burglaries and murders, they have a team on standby to help investigate and crack the case. One of the the first steps is having crime scene specialists collect latent fingerprints at the scene. The evidence is logged and checked into evidence lock up until investigators request an analysis.

Tucson police evidence examination specialist Abe Enochs says there are multiple layers in processing and identifying prints. He also says getting a clean and usable print is key.

"My jobs is to collect the prints and develop them so they have something to compare," he said. "I look at the item I have and I look to see if its something that's porous like a piece of paper or a water bottle and I'll different processes depending on that. If it's something that's a smooth and shiny surface, that's where we use super glue fuming where I take super glue and put it in the chamber and put the item in a warmer and when it starts to fume the super glue actually adheres to finger print residue."

The use of superglue is common and can help create a clear print, but techniques can also change depending on the evidence. Some evidence can have both prints and DNA and if DNA is present it's swabbed and sent to the DNA lab for analysis.

"I just take the piece of paper, put the chemical all on it, let it dry apply it again," Enochs said. "I'll steam it and see the purple color change and develop the prints. Normally with a bottle its DNA and with prints we have to get the prints first because any swabbing we do could damage the finger prints."

Once Enochs finishes his work, the photos are uploaded into a database and the information is sent to Meredith Atchison who takes over. Atchison focuses on latent print analysis and matching the prints, she also puts the prints in the TPD fingerprint identification system. Another part of her job is to testify in court.

"I'm going to look at the entirety of the impression distortion happening in the impression for any creases or scars that may help me identify orientation or location anatomically on a hand. Latent prints are impressions left behind by accident, I may touch a surface and thought I don't see latent impressions they may be there," Atchison said

Some cases can get turned around within a day depending on the investigation.

"The agency itself is recognizing the importance of the technology that we can use today to search the fingerprint databases," Atchison said

Atchison also says if you try to destroy your fingerprints, they will always come back.

"The resulting scarring from trying to damage your fingerprints is just as unique as your first ridges themselves. So it can actually make my job much easier to find somebody," she said

The results are reconfirmed and sent to detectives.