SCOTTSDALE, Ariz. – Police have arrested 35-year-old Matthew Dieringer in connection with the brutal murder of his roommate, 67-year-old Frank Quaranta, after a tip from the public led to his capture.
The case began when officers conducted a welfare check at Quaranta’s Scottsdale home and discovered him dead from apparent blunt force trauma. Evidence at the scene pointed to Dieringer, who had been living with Quaranta after the two met through a church-run homeless outreach program.
Dieringer was apprehended in Phoenix near 13th Street and Indian School Road, initially on a probation violation tied to a 2024 theft case. While in custody, police obtained a search warrant and collected forensic evidence, which helped confirm his connection to the homicide.
“He was taken to our jail, and we served a search warrant for forensic evidence,” said Scottsdale Police Sgt. Allison Sempsis. “Once we had that, we were able to tidy up any loose ends for the homicide case.”
Dieringer made his first court appearance on September 7, where his bond was set at $3 million. During the hearing, he disputed the charges and stated, “I believe that you are being given wrong information entirely about me and my name.”
However, prosecutors argued otherwise, citing strong evidence, including a presumptive DNA match to blood found at the scene. Brooke Gaunt, of the Maricopa County Attorney’s Office, described the killing as a “very violent and horrific murder.”
Prosecutors also highlighted Dieringer’s criminal past, including a 2020 conviction in Colorado for torturing and dismembering two dogs belonging to a former roommate. Gaunt requested a cash-only bond, citing the risk of flight and the severity of the crime. If convicted, Dieringer could face life in prison or the death penalty.
During the hearing, Dieringer called the legal proceedings “illegal” but ended his statement with, “God bless you and have God in your soul.”
Former FBI Supervisory Special Agent Lance Leising commented on Dieringer’s behavior, suggesting it reflected a pattern seen in dangerous offenders.
“It almost was an ego thing… like they felt they were smarter than their victims or the investigators,” Leising said.
The investigation remains ongoing, led by the Scottsdale Police Department.
