DNA forensics helping crack more property crimes

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DNA supervisor Kristine Deters demonstrated how she collects DNA from firearms at the BCA. (Star Tribune)

A potent crime-fighting tool once reserved for the most violent offenses, DNA testing is now helping solve more nonviolent crimes, including thefts, drug offenses and quality-of-life crimes such as vandalism and window-peeping.

Across Minnesota, scientists tested for DNA in more than 2,000 property crime investigations this year, according to the lab directors who oversee Minnesota’s three forensic labs accredited to test DNA. And that number is on the rise.

Scientists have found DNA on steering wheels and air bags in stolen cars, tools left at burglaries and on cables in stolen televisions. They’ve found DNA in saliva on half-eaten food left at crime scenes, including on a slice of pizza and a corn dog. They even found DNA on a dog treat handled by a thief.

One-third of the 3,500 cases processed for DNA at the Bureau of Criminal Apprehension Forensic Science Laboratory, which has offices in St. Paul and Bemidji, was for a property crime investigation, said its lab director.

About 62 percent of the 1,500 DNA cases handled at the Hennepin County Sheriff’s Office crime lab were for property offenses.

The Tri-County Regional Forensic Lab at the Anoka County Sheriff’s Office reports that about 60 percent of the 560 DNA cases it processed this year were for property crimes. In one case, the lab even swabbed and tested bicycle handlebars.

“We don’t ignore the property crimes,” said Hennepin County Sheriff Rich Stanek. “That is the gateway to the larger stuff.”

When DNA is found at a property crime scene, Minnesota scientists match it to a known offender’s sample in CODIS, the national DNA database, more than 70 percent of the time, lab directors said.

Many of these property and nonviolent crimes are viewed by police as nearly unsolvable without such DNA work.

“Residents really appreciate when we come to a crime scene and we put a lot of effort into it,” said Scott Giles, director of the Hennepin County crime lab.

Scientific leaps

Scientific advancements have made it possible for forensic scientists to test a wider array of items for traces of DNA. Back in 2000, it took a quarter-sized visible stain of blood or bodily fluids to test for DNA. Now scientists can test using microscopic amounts of genetic material, including skin cells left simply by handling an item called “touch DNA.”

“We can really get a lot more from a lot less,” said BCA lab director Catherine Knutson. The advancements have prompted BCA scientists to also conduct more DNA testing on guns and shell casings. In the past decade, the BCA has nearly tripled the number of DNA cases it handles.

In addition, robotics and automation are helping speed testing. Scientists can now test dozens of samples at a time.

Stanek said he believes using science to solve property crimes is part of the equation for dramatic crime reduction in his jurisdiction.

“It’s a huge investment — $4 million a year,” he said, referring to the lab’s annual budget. “The benefits are extraordinary for the residents of the community.”

The use of such sophisticated testing in property crime investigations isn’t slowing down violent crime investigations, lab directors say. BCA lab turnaround times have remained steady, and the Hennepin County lab has actually improved its times this year. Turnaround times at the Hennepin and BCA labs range from 30 to 50 days, depending on the type of case. The Tri-County lab, accredited in 2013, has a two-week turnaround time.

Catching burglars and other property-crime criminals can help reduce the violent crime rate, experts say.

“Individuals doing property crimes could escalate to violence,” said Angela Erickson, quality assurance manager at the Hennepin County lab.

Hennepin County Attorney Mike Freeman said the expansion of DNA testing into property crimes is helping get convictions. “It’s exciting for us. We can take a serial burglar off the street, which we have done a couple of times,” he said. “Every year we have learned to use DNA better.”

Prioritizing property crimes

The Hennepin County Sheriff’s Office Crime Lab emphasizes investigating property crimes in the suburbs. It provides lab services for all the suburbs in the county. Minneapolis police use the BCA lab.

“For us in the suburbs, property crime is a big deal,” said MinnetonkaPolice Chief Jeff Sebenaler. “We don’t have homicides, thank goodness.”

The sheriff’s crime lab routinely dispatches investigators to gather DNA and forensic evidence at the scenes of burglaries, car thefts and other property crimes. The sheriff’s lab staff also swabs and tests all firearms obtained through investigations for DNA, fingerprints and ballistics. Last year, the Hennepin County lab tested nearly 500 firearms.

“They treat every crime as a big one,” said Sebenaler, describing the crime lab’s work as quick and high-quality.

Robbinsdale Police Chief Jim Franzen, who oversees the small suburban department of 23 officers, said access to the county crime lab is helping his department solve some of the most challenging cases.

“We are using them more and more for property crimes,” Franzen said. “A lot of times we will have them come out and process a burglary scene. We don’t have anything else to go on. There is no witness or no evidence left behind. They are definitely helping out when we are at a dead end.”

Dog treat cracks case

This year, the Hennepin County sheriff’s crime lab helped solve an unusual Edina burglary. The culprit broke into a home on a couple’s wedding day and stole their wedding gifts. The thief brought Beggin’ Strip dog treats to distract the victims’ dog. One of those uneaten treats was left on a dresser. An officer bagged it and sent it to the lab. The thief’s DNA was found on the treat.

He pleaded guilty this summer.

Edina Detective Dave Carlson, who worked the case, said access to lab work is making a tangible difference.

“It helps our solve rate and it helps with convictions, because we can put the suspect at the scene,” he said.

Source: Star Tribune