The province’s police watchdog is investigating after a collision in Port Colborne early Friday morning left a motorcyclist critically injured.

The Special Investigations Unit (SIU) said a Niagara police officer initiated a traffic stop in the area of Highway 3 and Empire Road at 12:30 a.m. for two motorcyclists “travelling at high speeds.”

Shortly after, the motorcycles collided, the SIU said. One male rider was airlifted to a Toronto hospital with life-threatening injuries.

Meanwhile, the SIU said the other rider was taken by ambulance to a hospital in Hamilton and his injuries are not considered serious.

The police watchdog has assigned two investigators and one forensic investigator to the case and designated one subject official.

The SIU, which investigates the conduct of police that resulted in death, serious injury, or allegations of sexual assault, is asking witnesses to call 1-800-787-8529 or submit evidence online at https://siu.on.ca/en/appeals.php.