The Crown has dropped the charges against one of the officers in a shooting involving two Niagara police officers last year.

Det.-Sgt Shane Donovan was facing charges of aggravated assault and assault after Const. Nathan Parker was shot at a rural crossroads in Pelham, Ont., last year.

But those charges were dropped in a St. Catharines, Ont., court on Friday. There was no reasonable prospect of conviction, and time will show that any aggression from Donovan was in self-defence, said Joanne Mulcahy, Donovan's lawyer.

His actions were "fully necessary, fully justified and in defence of his life," Mulcahy said.

Donovan is an anticipated witness in the future trial of Parker, who's charged with resisting arrest, assaulting an officer and committing assault with a weapon.

The two were on duty last Nov. 29, part of a group of officers investigating a collision around Roland Road and Effingham Street.

Donovan, who headed up the Niagara Regional Police's collision reconstruction unit, is alleged to have fired his weapon multiple times. Parker, 53, was seriously injured and airlifted to Hamilton General Hospital, said the province's Special Investigations Unit.

It's still unclear what caused the altercation.

Parker is a 28-year veteran of the force. In that time, he has reportedly faced multiple disciplinary hearings under the Police Services Act.

According to local media, including the St. Catharines Standard, he pleaded guilty in 2015 to discreditable conduct and unnecessary use of force against a prisoner and was docked 120 hours pay.