Hundreds of Scottsdale’s cold criminal cases will be revived with a DNA sequence detection system courtesy of a $224,000 federal grant, police said.
Steve Garrett, manager of the Scottsdale Police Department crime lab, said the backlog of cold or “no suspect” cases is in the thousands. But only about 800 are good candidates for DNA testing, he said.
“It's going to be a lot of work on the detectives' part reviewing the cases and making sure they are still viable and have physical evidence,” Garrett said. “And it's going to be a lot of work on our end screening all that physical evidence to remove any possible DNA. And then to turn around and run the samples. It's going to be a long, arduous task.”
However, the new equipment will mean less laborious processes, faster results, cheaper costs and, hopefully, arrests, said Kris Cano Whitman, the department's DNA technical leader.
“It's basically going to cut the time in half,” she said.
The equipment will consume $50,000 of the grant from the National Institute of Justice. The remainder will go to supplies, additional training for crime scene technicians and criminologists, as well as overtime for the investigators with cases that stalled long ago.
Garrett said the goal with the grant is to track down burglary, robbery and aggravated assault suspects using biological material from crime scenes.
“When we obtained our first DNA grant, which we completed this past year, we looked at 88 different cases of sexual assaults in Scottsdale that had no suspects at the time,” Garrett said. DNA profiles were developed from 13 of 14 cases and were entered into the Combined DNA Index System national database, he said.
When three DNA samples came back identical from Scottsdale and Phoenix assaults in the mid-1990s, criminologists realized they were looking for a serial rapist, Garrett said.
The suspect, a known sex offender serving time for other assaults, was identified. He reached a plea agreement last year with prosecutors, Garrett said.
The national database recently has started accepting DNA samples from burglary, robbery and assault cases.
Scottsdale criminologists typically spend four weeks processing a series of DNA samples with two in-house genetic analyzers. The problem is some samples are not good candidates with too few genetic markers as to leave no doubt of a person's identity, Cano Whitman said.
The criminologists can't tell which samples are duds until the process is complete. The sequence detection system will screen out bad or invalid evidence, saving time, supplies and money, she said.
“We won't have to spend our time doing the screening. We can spend more time doing analysis,” she said.