"We never stopped investigating this case."
Scottsdale police have made an arrest in the 2015 murder of Allison Feldman.
Feldman, a 31-year-old medical sales rep, was murdered in her south Scottsdale home on Feb. 17, 2015.
Documents state she died from blunt force trauma and asphyxiation after being found by her boyfriend.
Now, police have arrested 42-year-old Ian L. Mitcham on a first-degree murder charge.
He was taken to jail on Tuesday night and booked. His initial court appearance is scheduled for 5 a.m.
"We are one hundred percent confident we have the right suspect," said Scottsdale Assistant Police Chief Scott Popp.
A DNA sample found at the murder scene was linked to a sibling of the suspect already in prison, using a process called "familial DNA testing."
"We collected over 400 items of evidence," said Popp. "We spent the next three years exhausting every lead... We've analyzed hundreds of items. We've conducted hundreds of interviews, and spent well over, 3-to-4 thousand personnel hours conducting this investigation."
After several years with no leads, Scottsdale police contacted DPS, and the process of the "familial DNA match" began.
"Scottsdale PD found an unknown DNA sample at the crime scene. We compared that sample to our DNA database of arrested offenders here in Arizona," said Col. Frank Milstead of the Arizona Department of Public Safety. "We came up with a family linkage to this person who was in custody. And then, through that information, they were able to identify the sibling of that person in custody. The familial DNA is off siblings, parents in the same bloodline You inherit blood traits from your parents and that moves through the process."
"I'm elated that this guy has been caught," said Allison Feldman's father, Harley Feldman. "We wish wouldn't be here, but if we're here, we're glad he's been caught by police."
Over the years, Feldman's family members had continued to share her story in hopes someone would have a key piece of information that would break the case.
Friends and family had never given up hope the case would be solved.
"We knew it was the evidence that would lead to an arrest, and that's essentially what happened," Harley Feldman said.
"I really, firmly believe that this is going to be solved. I truly do. I know there's going to be justice for Ally," said Feldman's best friend, Katie McCartin at the time.
"We all have developed a deep connection to the Feldman family over the years," said Popp. Everything we know about Allison, she was a beautiful human being. There was no reason whatsoever Allison should have been the victim of a violent crime in our city."
Feldman worked as a medical sales rep in the Valley. Her boss, Jeff Ciardi, had described her as his little sister.
"It's extremely difficult to think it's been three years since she passed," he said. "I still feel the emotions I feel that same night three years ago... having to call her friends and tell them the tragic news."
Popp said Scottsdale police spoke to Feldman's father Tuesday afternoon. He said they share a feeling of relief. "We feel relief that the murderer is not on the street anymore."
"Violent murder of a child is the biggest stress and trauma that the human body can ever go through," her mother, Elaine Feldman, had said at a candlelight vigil held in honor of her daughter.
Friends say Feldman had volunteered her time with young burn patients and was about to get engaged to her boyfriend.
"She was a loyal friend, a strong woman, vibrant, and full of life," said one of Feldman's close friends.