The province's Special Investigations Unit is investigating after a 36-year-old man in Sudbury was injured yesterday.
The SIU says shortly after midnight on Thursday, Sudbury Police were called to the area of Lloyd Street and Matthew Street.
While arresting a 36-year-old man, the SIU says there was an interaction. He was taken to hospital where he was treated with a shoulder injury.
Two investigators and one forensic investigator have been assigned to the case.
The SIU investigates cases involving police where there has been a death, serious injury or allegations of sexual assault.