LONDON, Ont. - Ontario's police watchdog has charged a London, Ont., police officer for allegedly assaulting a suspect during an arrest earlier this year.

The Special Investigations Unit says the incident happened in May when officers responded to a report of a man standing on the side of a road in the city.

The SIU says the officers arrested the 60-year-old man, but later released him "unconditionally."

The agency does not say what the man was doing or why he'd been arrested.

It only says that later that day, the man was transported to hospital with serious injuries.

The SIU says Const. Omar Hassan, 48, is facing one count of assault causing bodily harm.

He is due in court on Sept. 5.

The SIU is an arm's-length agency that investigates allegations of serious injury, death, or sexual assault at the hands of Ontario police officers.