PEORIA, Ariz. — A woman who attacked her cousin with a claw hammer, killing him inside his own home, then attempted to vacuum up the blood before calling authorities has been sentenced to 21 years in prison, according to court records.
Brianna Elise Zerth, 33, pleaded guilty in April to one count of domestic violence manslaughter for the death of Peter McKenna Jr., 33. A judge imposed the sentence Friday — the maximum allowed under Arizona law for the charge.
Background
According to investigators with the Peoria Police Department, officers responded to an emergency call just after noon on May 5, 2022, about a dead man at a home near 112th Avenue and West Diana Avenue. First responders found McKenna inside the residence and declared him dead at the scene after determining he had suffered multiple blunt-force trauma injuries.
Police learned that Zerth was related to McKenna, who lived in the home where his body was discovered. Court documents indicate Zerth told investigators she and McKenna had been drinking alcohol late into the night on May 4 before they began fighting. She claimed the specifics of the altercation were "blurry" and said she woke up to find him dead on the floor, surrounded by blood.
A preliminary investigation revealed Zerth's account of events that night would become central to the prosecution's case as it developed over the following years.
The Investigation
According to reports from AZ Family and KOLD-TV, Zerth told police she attempted to clean up the scene after discovering McKenna's body. She said she covered her cousin with a jacket and tried to vacuum up the blood that had pooled on the floor. She also reportedly attempted to pick up broken glass, explaining later that she was afraid her daughter might step on it.
Zerth eventually called police, informing them that McKenna was "stiff and cold to the touch."
Investigators noted the violent nature of the attack, which involved a claw hammer as the weapon. During legal proceedings, Zerth claimed McKenna was strangling her during their fight and caused her "significant trauma" — an examination reportedly corroborated some of her claims regarding injuries she sustained.
Zerth was initially arrested and charged following the incident but later released when prosecutors declined to formally charge her due to what they described as a lack of evidence. The case was subsequently reopened, leading to additional charges.
She was originally indicted on one count each of second-degree intentional murder, aggravated assault with a deadly weapon or dangerous instrument, and tampering, destroying, or altering physical evidence. As part of her plea agreement in April, prosecutors dropped the assault with a deadly weapon charge and the evidence tampering charge.
Court records show Zerth was credited with 1,056 days — approximately three years — served while awaiting resolution of her case.
Key Takeaways
- Peter McKenna Jr., 33, was killed inside his own home in Peoria, Arizona, on May 4, 2022
- His cousin, Brianna Elise Zerth, 33, admitted to attacking him with a claw hammer
- Before calling police, Zerth attempted to vacuum up the blood and covered McKenna's body with a jacket
- She pleaded guilty to domestic violence manslaughter and was sentenced to the maximum 21 years
- Prosecutors dropped charges of assault with a deadly weapon and evidence tampering as part of her plea deal
What's Next
Zerth will begin serving her sentence immediately at an Arizona Department of Corrections facility. The case represents one of several domestic violence manslaughter convictions secured by the Maricopa County Attorney's Office in recent years, authorities said.
McKenna's family attended the sentencing hearing, according to court records.