Indiana State Police are catching criminals using new software that has the ability to analyze evidence containing the DNA of multiple people.
Scientists in New Zealand and Australia designed the software in 2011 called STRmix. Indiana State Police implemented STRmix in November after validating the software for more than two years, the Times of Northwest Indiana reported.
“We tested every kind of situation that we could possibly think of,” said DNA supervisor Carl Sobieralski. “We ran samples through the program to ensure it was making the right decisions all the time. ... There were hundreds and hundreds of samples.”
The software recently helped secure charges against a Chesterton man in a June 2017 robbery by analyzing evidence from latex gloves believed to be worn during the crime. State Police used the software after determining the mixture of DNA on the gloves couldn’t be separated.
Sobieralski said police began using the software to reanalyze evidence in cases going back two years. He said STRmix helps analysts do what no human could.
“Mixtures of multiple people become so complex that the human brain isn’t really good at figuring them out,” he said. “You can’t take everything into consideration. You could falsely include people, and we don’t want to do that.”
The software combines biological modeling, statistical theory, computer algorithms and probability distributions to infer genotypes and calculate likelihoods for the DNA profiles from forensic samples.
Sobieralski said State Police anticipate the new software’s validity will be challenged in court.