Wisconsin Crime Labs use new DNA analysis program

Forensic scientists in Wisconsin are using new DNA technology called Strmix to better analyze...
Forensic scientists in Wisconsin are using new DNA technology called Strmix to better analyze multiple DNA samples.(NBC15)
Published: Mar. 11, 2020 at 7:04 PM CDT
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Starting this year, Wisconsin State Crime Labs are using software that untangles the web of DNA left at a crime scene.

was developed in New Zealand, and is now used by more than 50 labs in the United States, including Madison and Milwaukee.

"Work never stops, if we can't solve something, we keep working for decades if we have to," Administrator for the Wisconsin Department of Justice, Division of Forensic Sciences Katherine Roehm said about the work forensic analysts put into unsolved crimes.

Strmix aims to make that work easier.

“What we're able to do now is take mixtures of DNA, like three person mixtures that we weren't able to interpret before and we're actually able to interpret those," Roehm said.

That 'mixture' is made up of DNA from all of the people who may come in contact with the same piece of evidence on a crime scene.

"What happened before was if we had a three-person mixture, it would be too complicated to pull apart and we'd basically have to report back that it was inconclusive,” Roehm said. “Now using this software tool, we're able to enter the information into the system and actually get inclusionary and exclusionary conclusions."

But some people, like Kate Judson with the Center for Integrity in Forensic Sciences, are concerned about how reliable Strmix is.

"There are some problems with it being developed not using the normal guidelines that one would use to develop software, there are some questions about accuracy," Judson said.

Judson said that accuracy is important, especially in emotionally sensitive court cases.

"Anytime we are using probabilities or trying to put in numerical value on the likelihood that someone was present at a crime scene I think we need to be careful that we're using the best technology,” Judson said.

But for forensic scientists like Roehm, this is another tool in the toolbox.

"The role of the crime lab is to be that impartial, unbiased entity in the criminal justice system and this speaks to that," Roehm.

In January, employees with Wisconsin Crime Labs finished training the first group of scientists on how to properly test, using the new program. They’re currently in the middle of training their second crew.