The Royal Marines Police is a unit of the Royal Navy Police and the military police of the British Royal Marines. The RM Police is responsible for providing garrison policing services; law enforcement and crime prevention as well as general security advice to the command, and includes a Special Investigation Branch (SIB) section for the investigation of serious crime. RM Police personnel are recruited from within the trained strength of the Royal Marines, following completion of a first posting to a rifle troop in a Commando.