Former Local Resident Accused of Brutal Arizona Murder
Trevor Phipps
Just over five years ago, a 30-year-old Matthew Dieringer was wanted in Teller County for torturing, murdering and dismembering two dogs at a Florissant residence.
Dieringer was arrested a week later at a Denver metro hotel after a massive manhunt was launched.
Now, the criminal, who had previous ties with residents in Teller County, is accused of the fatal beating of an Arizona homeless advocate.
Earlier this month, Dieringer was arrested in Scottsdale, Arizona for first-degree murder. Authorities said that Dieringer brutally beat 67-year-old Frank Quaranta to death at his home that he may have shared with Dieringer on Sept. 1.
On Sept. 6 a resident walking his dog spotted Dieringer at a park in Phoenix. Authorities arrested Dieringer on a probation violation, then later escalated the charges to first-degree murder after they matched his DNA at the crime scene.
After his arrest and during his court date, Dieringer told the judge, authorities have the wrong person. Despite his pleas, Dieringer remains in jail on murder charges with a $2 million bond. If convicted, Dieringer could face life in prison or possibly the death penalty.
Crime History Dates Back to Earlier Teller County Incident
On July 20, 2020, the Teller County Sheriff’s Office issued a press release stating that Dieringer (who was 30 years old at the time) was wanted on animal cruelty charges after he brutally beat and killed his roommates dogs in Florissant. According to the arrest affidavit, Dieringer brutally beat and tortured the victim’s brown, seven-year-old Australian Cattle Dog, “Suka,” and the victim’s other black dog, “Hayoka.”
Both dogs were killed after being beaten with a brunt object. After the deaths, Dieringer dismembered one of the animals.
Dieringer fled the Teller County property after the incident and was on the run for several days. According to the Teller County Sheriff’s Office, people from out of state reached out to give money and aid in the search for the suspect. The incident commanded a tremendous amount of state and national attention.
Then on July 26, Arapahoe County deputies arrested Dieringer after receiving information from Teller County that he was staying at the Days Inn Motel on East Geddes Avenue in Centennial. After a brief scuffle, Dieringer was arrested on two felony charges of animal abuse.
Dieringer was eventually convicted of animal abuse charges in 2023. He then spent 18 months in prison before continuing his crime spree.
According to experts, the violent attack on animals was a sign that Dieringer’s crimes could escalate to violence toward humans. “It’s not so much the violence to the animals, or the animal abuse, it’s really that people are desensitized to these issues early on in life and violence or animal abuse is indicative of that desensitization,” retired FBI Supervisory Special Agent Lance Leising told Fox 10 Phoenix.
Suspect’s Crime Spree Continued in Arizona
At the time of Dieringer’s most recent arrest, he was on probation after he pleaded guilty for theft and assault in 2024. On June 20, 2024, Dieringer attempted to assault a man who was walking down the street. He ended up stealing the man’s sunglasses.
That same day, it was reported that Dieringer approached a woman and asked if he could pet her dog. But then, instead of petting the dog, Dieringer picked up the 14-year-old pet and threw it violently to the ground. He then walked up to another woman and kicked her dog. The kick was hard enough to cause the animal to fly out of its leash and into the road. Dieringer ended up pleading guilty on misdemeanor assault charges and theft for the 2024 crime.
According to news reports, Dieringer’s latest victim (Frank Quaranta) worked at the Wesley United Methodist Church in south Phoenix helping the homeless. Quaranta was known to offer his house to homeless people and those that knew him told authorities he had been letting Dieringer stay with him for several months leading up to his death. At one point, Quaranta asked his friends how he could get him to leave.
Reports say that the now 35-year-old Dieringer was “manipulative and charismatic” and often befriended people to get a free place to stay. People who knew the victim told authorities that Dieringer exhibited strange behavior up until the alleged murder.
“People at the homeless outreach who knew that Matthew was living with Frank or staying with him, I just know that they were concerned about Matthew and his behaviors,” said Scottsdale Police Sgt. Allison Sempisis, according to news reports.
On Sept. 1, officers responded to Quaranta’s apartment complex for a welfare check after the victim didn’t show up for work or answer his phone. After the police noticed blood on the front door handle, they forced their way into the house. Once they entered, officers found Quaranta, apparently dead at the top of the stairs with head wounds and other extensive injuries.
Inside the home, authorities found two bloody statues lying next to the victim’s body. They also found bloody handprints, footprints and clothing at the crime scene.
Authorities first arrested Dieringer on a probation violation. The suspect refused when they tried to get his DNA from buccal swabs, so officers filed another search warrant for a blood draw. After his blood was drawn, investigators linked Dieringer’s DNA to the crime scene.
