A man who allegedly stabbed his 9-year-old son to death in a San Jose park Sunday, July 13, 2025 and was subsequently killed by police intended to die via "suicide by cop," according to San Jose Police Chief Paul Joseph in a press conference on July 14. Mateusz Dzierbun of Fremont allegedly killed his son then called 911 posing as a "hysterical" witness to ask that officers be sent to Cataldi Park to save the child, even giving a detailed description of himself as the suspect. (Screengrab from San Jose Police Department YouTube via Bay City News)

A man who allegedly stabbed his 9-year-old son to death in a San Jose park and was subsequently killed by police intended to die via “suicide by cop,” San Jose Police Chief Paul Joseph said Monday. 

Mateusz Dzierbun of Fremont allegedly killed his son then called 911 posing as a “hysterical” witness to ask that officers be sent to Cataldi Park to save the child, even giving a detailed description of himself as the suspect, Joseph said during a news briefing. 

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Kiley Russell writes primarily for Local News Matters on issues related to equity and the environment. A Bay Area native, he has lived most of his life in Oakland. He studied journalism at San Francisco State University, worked for the Associated Press and the former Contra Costa Times, among other outlets. He has covered everything from state legislatures, local governments, federal and state courts, crime, growth and development, political campaigns of various stripes, wildfires and the aftermath of Hurricane Katrina.