A Modesto man has been convicted of first-degree murder in connection with a 2022 shooting that resulted in one death and left his former girlfriend injured, according to the Stanislaus County District Attorney’s Office.
Matthew Douglas Cook, 42, was found guilty by a jury last month for the killing of 36-year-old Matthew McDonough on September 29, 2022. The verdict included findings that Cook acted intentionally, deliberately, and with premeditation. Jurors also determined that he personally and intentionally discharged a firearm during the incident. Cook is facing a life sentence at his upcoming sentencing hearing.
Prosecutors said the incident arose from Cook’s increasing jealousy after his girlfriend ended their relationship earlier in 2022. The district attorney’s office reported that Cook had repeatedly threatened to harm any man seen with his ex-girlfriend.
On the day of the shooting, Cook reportedly watched his ex-girlfriend as she left with McDonough. He then followed them by car and approached their vehicle near Mitchell Road and Riverside Drive before firing into it. McDonough was struck once in the chest but managed to pull over before collapsing, which prosecutors noted may have prevented further injury to his passenger.
In addition to murder, court records show Cook was convicted of shooting at an occupied vehicle and assault with a firearm involving his ex-girlfriend. Firearm enhancements were also found true by jurors.
Cook’s sentencing is set for January 21, 2026.
