Ian L. Mitcham, 42, was arrested in Pheonix yesterday and faces first-degree murder charges in the death of 31-year-old Allison Feldman. (Photo: Courtesy of the Scottsdale Police)

The murderer of 31-year-old Allison Feldman had left DNA in her home, but that genetic profile did not show up in any state or national databases for more than three years.

But when Arizona law enforcement tried familial DNA searching for the first time on the high-profile killing, it pointed to the murderer’s brother—and then the killer himself, Arizona authorities announced Tuesday.

Ian L. Mitcham, 42, was arrested in Phoenix yesterday morning, the culmination of more than three years of an investigation that had reached a dead end before the use of the advanced database search, authorities said.

“We were at a point of impasse,” said Assistant Chief Scott Popp, of the Scottsdale Police Department. “We were out of leads and still had a very violent offender on the loose.”

Feldman was found dead in her home on East Monterey Way in Scottsdale in the late afternoon of Feb. 18, 2015, by her boyfriend.

Authorities combed through the home for four days, collecting minute traces of forensic evidence. Eventually the police collected 450 pieces of physical evidence, and they interviewed more than 300 people, said Popp. Some 160 buccal swabs were collected from potential suspects.

“CODIS was continually searched. We exhausted all leads. This was a dead end,” said Popp. 

Arizona and its Department of Public Safety began instituting familial DNA this past November, and the Feldman murder was the first case attempted, authorities said at its Tuesday press conference.

The state took between six and eight months to set up its familial DNA process and software, and to hone the expertise to look for partial matches in the state and national databases, according to Col. Frank Milstead, the director of the Arizona DPS.

The rules include: a cold case homicide or crime of extreme violence, and one where all leads have been exhausted.

The Feldman homicide met all the criteria.

Last Thursday, the DNA from the crime scene partially matched an Arizona prison inmate: a man who was convicted of multiple counts of child molestation in the 1990s, and who is not eligible for release until the 22nd century.

The male relative of the inmate, one who would match the Y-STR genetic profile closely enough, was identified as Mitcham.

Mitcham had been arrested one month before the Feldman killing for a DUI in Scottsdale. The police had held onto the blood draw ever since, Popp said.

“That blood was to be disposed of so for us we did not need a separate warrant,” said the Scottsdale assistant chief. “It was (an) already adjudicated case, and ready for disposal.”

Why the sample ready for disposal was not disposed of was not immediately clear.

Popp said the blood proved cause for arrest.

“We did a direct comparison of Ian’s blood to our murder suspect’s DNA profile that we had from the crime scene—and that was our direct connection,” he said.

Steve Garrett, forensic services director for Scottsdale Police Department, said only one male relative had to be checked out from the inmate’s circle—as opposed to cases in other states, which have required checking out 10 to 15 persons of interest, potentially.

Still, the total tab for the familial breakthrough was approximately $35,000, between staffing hours and expensive reagents, according to Popp.

Mitcham now faces first-degree murder charges for Feldman’s death.

Arizona is now the 12th state to implement familial DNA searching. Four more cases in the state are now being considered for the tool’s use.