Police 'fingerprint' car tyres

Auckland crime scene officer Glen Powell with some of the tyre tread patterns on a database he has developed. Picture / Dean Purcell

It's not quite as flash as the forensic gadgets on shows like CSI but a tyre print database created by an Auckland crime scene officer is becoming a vital crime-solving tool.

Glen Powell's tyre print identification system means police no longer have to photograph a tyre mark from a crime scene, and then go shop to shop trying to identify what kind of car it came from.

The 28-year-old non-sworn officer joined the police in 2002, bringing with him a tyre tread pattern and vehicle specification database that he developed as part of his masters degree in forensics.

Since then he has grown the list to include more than 300 tyre prints from more than 50 brands of New Zealand tyres - and it's proving its worth.

Using his database Mr Powell can tell what brand of tyre left a mark at a crime scene and sometimes even what kind of car left the tracks.

Mr Powell said before his database police had to take a cast of the tyre mark and then refer to an American manuel of tyres - which often didn't include New Zealand brands - or go shop to shop to try and make a match.

Now they can simply contact Mr Powell at Papakura station, give him a description and photograph of the tyre mark and he'll do all the work.

Keying in a couple of features from the tyre he can search the database and narrow the possibilities down to two or three possible brands. Mr Powell then does a visual comparison and can tell the investigating officer what brand of tyre the mark was made by within 24 hours.

If there are marks from two wheels he can also use his track dimension database to suggest what kind of car left the marks.

Mr Powell said his tyre print identification system has already helped in a number of serious crimes, including a rape and homicide.

In the rape case he was able to tell police the kind of car he believed the rapist was driving, which narrowed down a list of suspects. When police found the man, he had the car Mr Powell's database had suggested.

Detective Senior Sergeant Richard Middleton, district CIB administration supervisor, said he applauded Mr Powell's initiative.

"It's an awesome thing that's he done and he's done it off his own cognizance. It's not like he's had input from the department and he's now made it available. It's not only helped in the district but also nationwide. It's certainly helped in a homicide down in the Bay of Plenty. It's a really good asset to have."

Mr Powell said he used the database about once a week to help solve crimes, mainly in Auckland. He hoped to use it more often when police around the country heard about it.