Ontario's Special Investigations Unit is investigating after a fatal crash involving a motorcycle and a police cruiser.

The incident took place around 11:17 p.m. Saturday. An officer with the York Regional Police was driving a marked police cruiser on Queensville Side Road between Woodbine and Leslie when the cruiser collided head on with a motorcycle, according to the SIU.

The motorcyclist died in the collision, SIU said.

The SIU has assigned three investigators, two forensic investigators and a collision reconstructionist to probe the circumstances of the incident.

The SIU is called in to investigate whenever police are involved in an incident that results in a death, serious injury, or allegations of sexual assault.

Witnesses are asked to contact the SIU lead investigator at 1-800-787-8529 ext. 1935.