Inset: Matthew Dieringer (Scottsdale Police Department). The townhome complex where Matthew Dieringer allegedly killed 67-year-old Frank Quaranta in Scottsdale, Ariz., last week (AZFamily/YouTube).
A “manipulative” and “charismatic” homeless man in Arizona known for “befriending others” has been arrested for allegedly killing a 67-year-old man inside his Scottsdale townhome, cops say.
Matthew Dieringer, 35, is accused of killing Frank Quaranta — who lived at a residence near 68th Street and McDowell Road — in what cops are calling a “targeted attack” that was uncovered Monday afternoon during a welfare check after Quaranta failed to show up for work, according to the Scottsdale Police Department.
Dieringer is a Colorado native who was convicted in 2020 of beating and dismembering his roommate”s two dogs. He received credit for 705 days served after being given an 18 month prison sentence before relocating to Arizona, according to court records.
“He has a history of experiencing homelessness, and has been described as manipulative and charismatic, often befriending others to assist him with a place to stay,” SPD officials said in a Friday press release while searching for Dieringer, who was arrested on Saturday. “If Dieringer is seen, use caution and do not approach; call 911 immediately,” cops warned.
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Police say Quaranta was killed last Monday, Sept. 1, inside his home. It’s unclear how he and Dieringer allegedly met.
“The welfare check call came into Scottsdale PD at about 1:30 p.m. on September 1, when the victim did not report to work,” SPD officials said. “Responding officers were unable to contact the victim any other way and forced entry inside the residence to check on Quaranta. Tragically, Quaranta was found deceased inside. Detectives and crime scene specialists spent the next several hours processing the home for evidence.”
Court records show Dieringer has had multiple run-ins with the law in both Arizona and Colorado, with a recent guilty plea being entered for theft in April and charges for assault stemming from a June 2024 incident. He also has prior arrests for criminal mischief and burglary.
In 2020, Dieringer killed and dismembered two dogs belonging to a roommate of his in Teller County, Colorado, with cops entering their residence to find the walls covered in blood and evidence of a struggle, including multiple holes and a blood spatter spot that looked like Dieringer was slamming the animals, according to local ABC affiliate KRDO.
“The scene we went into was difficult,” said Trixie Hudspeth, Teller County Sheriff’s Office Animal Control Officer, in a statement to the outlet.
According to KRDO, neighbors reported hearing yelling and seeing Dieringer in an “enraged mental state” on the night before authorities arrived at the home. The dogs’ remains were found in a plastic tote and bathtub drain, including tooth fragments and dog hair.
Dieringer later pleaded guilty to felony aggravated animal cruelty. He was being held without bond over the weekend for Quaranta’s death. Cops have not released information on what charges he is facing.
