Ontario's police oversight body is investigating after Brantford police fired an anti-riot weapon at a 51-year-old man on Tuesday.

In a news release the following day, the Special Investigations Unit said "preliminary information" suggests that in the afternoon, enforcement officers went to a residence at Brant Avenue and Henrietta Street to issue an eviction notice.

There, they "observed" a man with an "edged weapon" and called Brantford Police Service for help. Police attempted to negotiate with the man and several hours later an officer inside the residence fired an anti-riot weapon at him multiple times, striking him, the release said.

Anti-riot weapons are described as being less-lethal than regular guns and can fire rounds designed to hurt but not kill someone.

Police arrested the man and took him to hospital for a "serious injury," the SIU said.

The SIU investigates incidents involving police officers, special constables of the Niagara Parks Commission or peace officers under the Legislative Assembly Act that may have resulted in death, serious injury, sexual assault or a weapon being fired at someone.