Det.-Sgt. Shane Donovan testified Tuesday it was "either me or him" when he fired at least 10 shots at his fellow Niagara Regional Police officer, Const. Nathan Parker, in November 2018.
Parker had attacked him with "haymaker" punches and pulled out his baton, then his firearm, Donovan told the court, causing him to fear for his life and pull the trigger until Parker went down.
"I knew if he got the firearm up on me, then he would kill me — and it was either me or him," Donovan said. "So I fired my gun until he dropped his gun."
The sergeant's testimony took up most of the first day of the judge-only trial at the Ontario Court of Justice in Hamilton.
But while Donovan is the person who fired the shots, Parker is the one on trial.
The 55-year-old is charged with assault with intent to resist arrest, assaulting a police officer and assault with a weapon, which court heard covers a service-issue baton and sidearm.