Controversial DNA testing technique used in Feldman murder case

The recent arrest in the brutal 2015 murder of a Minnesota native in Arizona centers around a controversial DNA technology.

When Scottsdale, Arizona police kept running into dead ends in the murder case of Excelsior native, Allison Feldman, her family pushed them to use a new DNA technique, called familial DNA testing, to find her killer.

Tuesday, police arrested 42-year-old Ian Mitcham as the suspect in Feldman's death. They linked his DNA found at the crime scene to his brother who was already in prison for a different crime.

“The Y chromosome shows that it’s a male, so they knew that whoever the sample came from it came from a male,” said University of Minnesota human genetics Professor William Oetting.

Prof. Oetting says DNA testing is nothing new, but it's being used more in law enforcement and that's become controversial.

“Once you have a partial match and you think that it’s a member of the family, now every member of that family becomes a suspect and every member of that family needs to be tested,” said Oetting.

In Minnesota, the Bureau of Criminal Apprehension used familial DNA testing several years ago solve a cold case in Duluth. BCA Superintendent Drew Evans says police departments do not use the method frequently.

“This is a technology that is very time intensive it wouldn’t be efficient to utilize this technology in every single case," said Evans.

The technology also raises questions about data privacy. In Allison Feldman's case, the suspect had been arrested a month before her murder for a DUI, so police had his blood sample on file. 

Criminal defense attorney Joe Tamburino says there could be concerns from a legal standpoint.

“His brother might come in with his attorney and say ‘Hey wait a minute, that’s my privacy—I have privacy in my own genetic make-up,’" said Tamburino.