Police in Arizona say they have arrested the man suspected of murdering a 31-year-old Scottsdale woman more than three years ago.

Ian Mitcham, 42, was arrested by Scottsdale Police on Tuesday at approximately 9:57 a.m. on suspicion of first-degree murder after DNA evidence allegedly tied him to the brutal killing of Allison Feldman.

Feldman was found dead in her home by her boyfriend on February 18, 2015. Court documents say she was found nude, and her entire body smelled of bleach. She ultimately died from head trauma.

Over the course of a three-year investigation, officials said that is was “forensic evidence” that led to Mitcham’s arrest.

“From the start, we have stated that this investigation is and has been driven by forensic science and evidence. A DNA profile was developed from evidence at the scene, but unfortunately no match was found in the current databases,” a press release from the Scottsdale Police Department Public Information Office stated.

It was through the use of familial DNA testing in 2017 that police suspected Mitcham. Familial testing takes DNA evidence and compares it to genetically similar samples.

“The process widens the search parameters of the offender data base to identify people that may be close relatives of the person who committed the crime,” the press release said. “Using this process, we were able to develop a match, which ultimately led to Mitcham’s arrest today.’

Police have yet to determine a link between Mitcham and the victim, Assistant Chief Scott Popp said at a press conference on Tuesday.

The Associated Press contributed to this report.