A piece of DNA-analyzing equipment used by the Scottsdale Police Department for the past two years has identified new evidence from the scenes of 11 unsolved cases that were missed by earlier
Although no arrests have been made yet, detectives at least have more leads than they had before, said Kris Whitman, the department’s DNA technical leader.
“If you can provide an investigative lead to the detectives, that’s part of our job,” Whitman said.
“By analyzing the DNA, we can also eliminate a suspect who wasn’t at the scene.”
Police touted the 310 Genetic Analyzer, obtained with a $100,000 federal grant, as a key component in helping with decades-old cases including homicides, sexual assaults and property crimes.
Since the crime lab installed the equipment, 118 cold cases dating between 1996 and 2003 were identified as having more DNA samples, said Steve Garrett, police forensic services manager.
Of those, 11 cases recently were passed on to detectives because an additional DNA sample from another person who was at the crime scene was identified, Garrett said. The analyzer can identify 13 DNA profiles in evidence such as blood, semen or saliva samples, Garrett said.
Searching for new evidence is accomplished by screening old evidence for stains on a contact area, such as on a cigarette butt or piece of clothing.
The stain is extracted from the piece of evidence, and the DNA cells are isolated.
The DNA then is amplified or enlarged in the analyzer so it can be studied, Garrett said.
It takes four weeks to completely analyze a DNA sample.
“If you can eliminate one of those people off the streets who committed a rape or homicide, having the analyzer is worth it,” Garrett said.
“Or, if you can keep one person from being charged, it’s worth it.”