As already indicated, in almost all circumstances and regardless of whom you complain to, it will be police who investigate your complaint. A complaint made directly to the police will be handled according to how the ESD views the seriousness of your allegations. A complaint of serious misconduct, that is, if the alleged conduct amounts to a criminal offence punishable by imprisonment, or is disgraceful, or is other conduct likely to damage the reputation of the police force, is required to be formally investigated.

Police have a discretion not to investigate less serious complaints, but to deal with them as "customer service issues". These complaints, including allegations such as rudeness or failure to investigate the report of a crime, will usually be handled quickly and relatively informally at a local or district management level. Police also have a discretion enabling prompt dismissal of what they consider trivial complaints. If you think the ESD has wrongly characterised or dismissed your complaint, you should complain to the OPI.

Investigations generally include one or several long interviews between the officer assigned to investigate the complaint and the person complaining. The length of the interview depends on the seriousness of the complaint, the clarity of the complainant and the complexity of the factual scenario into which an investigation is being undertaken. Subsequently, police will interview witnesses and undertake various avenues of investigative inquiry. On occasions legal and scientific advice is obtained.

Most of the investigating personnel in the ESD, and local police district personnel who are assigned to investigate complaints, are experienced. Many of them are detectives. Spending time with the ESD is part of some police members' progression through the hierarchy of the police force.

Once the investigation is completed, which typically takes a number of months, the police file is referred to the officer in charge of the ESD. A determination is made on whether the complaint is found to be substantiated.

If the complaint is found to be substantiated, or if the investigation uncovers matters not raised by the complainant that indicate impropriety on the part of a police member, the police will decide whether or not to initiate disciplinary proceedings, or to caution or counsel the member. The complainant is advised of the outcome of their specific complaint, but not usually of other issues the investigation may have uncovered.  Where the complaint is made to the OPI and the OPI have maintained a review role, the OPI will provide a reporting letter.  In both cases, the letter is usually very brief and does not include the investigation report.

The Police Integrity Act 2008 (Vic) sets out the OPI's functions and powers. These include, but are not limited to, conducting investigations into police corruption and serious misconduct, analysing systems within Victoria Police to prevent police corruption and serious misconduct, and publicly exposing police corruption and serious misconduct.

The OPI's role in relation to police complaints is to ensure that:

The OPI has a number of investigative powers to assist in its investigations, including powers to:

Whether you make your complaint to the ESD or to the OPI, it is likely that the police will investigate your complaint in the first instance. Where the complaint is against a very senior officer, or relates to serious problems with police practices or procedures, or where the OPI considers it is in the public interest to do so, the OPI may investigate from the beginning. The OPI can review investigations and may require police to conduct further investigations or may conduct further investigations itself. As well as ensuring complaints are handled properly, reviews of police investigations allow OPI to identify broader systemic issues that may need to be investigated.

If you have any doubt about how your complaint might be handled, it is best to first contact the OPI, which will be able to provide you with advice and your options, in confidence.

People of Aboriginal or Torres Strait Islander descent who have a complaint about the police can contact the OPI's Aboriginal Liaison Officer (see: "Contacts", below).

If you are unhappy with a decision of the OPI you can request an internal review of its decision. An OPI staff member independent of the original decision maker must conduct this review.  Beyond this internal complaint, you can complain to the Victorian Ombudsman and in some cases seek review by the Supreme Court and/or the Special Investigations Monitor.

See also: Chapters 21*6 Freedom of Information and 21*4 Ombudsman.