The Mental Hygiene Police (MHP) was a law enforcement agency in the People's Republic of Haven under the auspice of the Bureau of Mental Hygiene, charged with finding and arresting people who dealt in knowledge and material that was deemed illegal, such as the history of Haven in the pre-People's Republic era. After his death and the fall of the Legislaturists, the MHP, along with every other Legislaturist security force, was absorbed in Oscar Saint-Just's Office of State Security.