Police authority can be misused by individual officers or entire departments, or the national police force as a body may be the instrument for political repression.
Individual abuse of law enforcement authority includes extortion, accepting bribes to cover-up crime, and conspiracy or participation in criminal acts. Individual police officers may unjustly use excessive violence or unnecessarily 'shoot to kill' to apprehend or restrain criminals or suspects. Police departments, local station-houses or constabularies may have policies of protecting vice and gambling; of 'shaking-down' businesses; of harassing minorities and youths; and of maintaining officers on the payroll who are not regularly present for duty. As an instrument of the state, police may be used for surveillance, for maintaining dossiers on civilians, and for unjustly imprisoning civilians.