The provincial Special Investigations Unit is imploring witnesses to come forward after a man fractured his leg in two places during an arrest on a city bus Tuesday.

It happened just after 9 p.m., when police were called to the area of Stintson Street and Erie Avenue about a man who was reportedly fighting with other passengers on a city bus.

Police say an “altercation” with officers ensued when they tried to arrest him, but after a short struggle he was taken to police headquarters downtown.

When they got there, the man told police his leg was injured. An ambulance crew was called and the man was taken to hospital for medical treatment. According to the SIU, the man suffered a fractured femur and ankle.

The SIU has assigned two investigators and one forensic investigator to probe the incident. SIU investigators want to speak with anyone who was riding the HSR between 8:30 p.m. and 9:30 p.m. on July 1 and who saw the arrest take place on Stinson Street and Erie Avenue. Witnesses are asked to contact the lead investigator at 416-622-2150 or 1-800-787-8529 extension 2150.

The SIU is an arm’s length agency that investigates reports involving police where there has been death, serious injury or allegations of sexual assault.