FOR IMMEDIATE RELEASE

Suspect Mateusz Dzierbun

DECEASED

On July 13, 2025, at approximately 3:23 PM, San José Police Department Patrol Officers responded to a report of a stabbing at Cataldi Park in the city of San José. Upon arrival, Officers located an adult male suspect armed with a large kitchen knife who was hunched over a bleeding 9-year old child. The suspect refused to drop the knife and follow commands, despite officers' attempts to de-escalate. 

During the verbal exchange, the suspect abruptly stood up, raised the knife, and charged at the officers prompting an officer involved shooting. Officers immediately began to assess the child for injuries and determined he was suffering from multiple stab wounds and was already deceased.

Officers took the suspect into custody and summoned paramedics to the scene. The suspect was transported to a local hospital where he was ultimately pronounced deceased.

The San José Police Department Homicide Unit responded to the scene and initiated a thorough investigation. Detectives learned that the suspect was the child's father and the reporting party. Detectives believed the suspect murdered his child in the park and called police in order to force a deadly confrontation upon their arrival.

The suspect was identified as 48-year-old Mateusz Dzierbun of the city of Fremont.

The identity of the victim will be released by the Santa Clara County Office of the Medical Examiner.

This incident is being investigated as the City's 13th homicide of 2025.

“I cannot imagine how scared this child must have been when the person meant to be their protector became their attacker,” said San José Mayor Matt Mahan. “As a parent and as a human being, there are no words to describe how horrific and heartbreaking this act of violence is. I’m grateful to our police department for responding swiftly and professionally to bring accountability in the face of such an unthinkable crime.”

“There are no words to ease the horror of this tragedy,” said SJPD Chief Paul Joseph. “Our officers were faced with an unthinkable scene and responded with urgency, courage, and professionalism. The San José Police Department grieves alongside the victim's family and our community, and we remain steadfast in our commitment to finding answers in the wake of this senseless act of violence.”

Anyone with information is asked to contact Detective Sergeant Varela #3638, or Detective Montoya #3644 of the San José Police Department’s Homicide Unit via email: 3638@sanjoseca.gov and/or 3644@sanjoseca.gov or at 408-277-5283.

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