The Major Crime Investigation Unit (MCIU) was formed in July 2002 to respond to incidents of the most serious crime.

The unit assists districts in establishing and operating dedicated major incident rooms staffed by specialist investigative personnel.

The MCIU also comprises a very successful Cold Case Review Team and has overall responsibility for co-ordination of the Constabulary's Family Liaison Officers (FLOs).

Family Liaison Officers support the families of homicide victims or persons killed as a result of criminal activity.