KITCHENER -- Ontario's police watchdog is investigating an incident that happened in Kitchener on Tuesday that left a man with serious injuries after he fell from a bridge.

According to a news release from the Special Investigations Unit (SIU), the Ontario Provincial Police received a call about a man running on Highway 8 near Fairway Road.

Officers responded to the call, which came in at around 10:15 p.m., and found the man. There was a brief struggle but the man managed to get away on foot.

"Shortly after, the man fell from a bridge to the ground approximately 12 metres below," the news release read in part.

"The man was airlifted to hospital for treatment of serious injuries."

Officials have only identified him as a 31-year-old man.

The SIU said that three investigators and two forensic investigators were assigned to the case. They have so far designated two witness officers and one subject officer.

Anyone with video evidence or information regarding this case is asked to contact the SIU's lead investigator at 1-800-787-8529.

The SIU investigates reports involving police where there has been serious injury, death or an allegation of sexual assault.