PEORIA, AZ – A violent family dispute that ended in a fatal hammer attack and a disturbing cleanup attempt has resulted in a decades-long prison sentence for a 33-year-old Arizona woman. Brianna Elise Zerth was sentenced Friday to 21 years behind bars after admitting to killing her cousin, Peter McKenna Jr., during a confrontation inside a Peoria home.
Zerth pleaded guilty in April to one count of domestic violence manslaughter in connection with the May 4, 2022 killing. Court records show the sentence is the maximum allowed under Arizona law for that charge, with credit for 1,056 days already served.
Investigation and initial response
Officers were called just after noon on May 5, 2022, to a home near 112th Avenue and West Diana Avenue after a report of a मृत man inside. McKenna, 33, was found with multiple blunt-force trauma injuries and was pronounced dead at the scene.
According to police, Zerth told investigators the two had been drinking late into the night when a fight broke out. She said the details of the altercation were “blurry,” and claimed she woke up to find McKenna dead on the floor in a pool of blood.
Authorities said Zerth admitted to attempting to clean the scene after the attack. She told police she covered McKenna with a jacket and tried to remove blood, including using a vacuum. She also said she picked up broken glass because she feared her daughter might step on it.
She later contacted authorities, reporting that McKenna was “stiff and cold to the touch.”
Claims of self-defense and charging history
Subsequent reporting indicated Zerth later told investigators that McKenna had been strangling her during the altercation and caused “significant trauma,” which was corroborated by an examination.
Despite the initial arrest, prosecutors at first declined to file formal charges, citing insufficient evidence at the time. The case was later refiled, and Zerth was indicted on charges including second-degree murder, aggravated assault with a deadly weapon, and tampering with evidence.
As part of the plea agreement reached earlier this year, those additional charges were dropped. Zerth instead pleaded guilty to the reduced charge of domestic violence manslaughter.
Sentencing details
Court records confirm the 21-year sentence represents the statutory maximum for the offense. Zerth will receive credit for just under three years already spent in custody.
The case concludes more than three years after the killing, which investigators said stemmed from a late-night argument that escalated into deadly violence inside the victim’s home.
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