As stated in its motto, the mandate of the Special Investigations Unit is to maintain confidence in Ontario's police services by assuring the public that police actions resulting in serious injury or death are subjected to rigorous, independent investigations.

Any such incident of death or serious injury which may reasonably fall within the SIU's jurisdiction must be reported to the SIU by the police service involved and/or may be reported by anyone else.

If the information available at the time of the report leaves any question regarding the SIU's jurisdiction, a review is done of the reported facts. When this preliminary step, which is part of the investigative process confirms the facts, a full-scale investigation is undertaken and reported upon to the Attorney General. If, on the other hand, there continues to be a question about jurisdiction, the Director is consulted and may, if appropriate, exercise his/her discretion to terminate further inquiries.

At the conclusion of a full investigation all of the evidence gathered is carefully considered. If that evidence supports a reasonable belief that a criminal offence was committed, the Director will cause a charge(s) to be laid and a public trial will be held.

If the evidence revealed in the course of an investigation does not support a reasonable belief that a criminal offence was committed, the investigative file will be closed. When files are closed the SIU provides all possible information concerning the investigation (subject to the Freedom of Information and Protection of Privacy Act), to both the involved parties and the public.