[1] : WordNet (r) 2.0

secret police
     n : a police force that operates in secrecy usually against
         persons suspected of treason or sedition

[2] : Moby Thesaurus II by Grady Ward, 1.0

52 moby thesaurus words for "secret police":
   cheka, fbi, gestapo, interpol, mp, mvd, mounties, nkvd, ogpu, rcmp,
   sp, scotland yard, bugging, cloak-and-dagger work, constabulary,
   counterespionage, counterintelligence, county police,
   electronic surveillance, espial, espionage, following,
   highway patrol, intelligence, intelligence work,
   law enforcement agency, military intelligence, military police,
   observation, police, police force, political police, posse,
   provincial police, riot police, secret service, security force,
   shadowing, shore patrol, special police, spying, stakeout,
   state police, surveillance, tactical police, tailing, trailing,
   troopers, vigilance committee, vigilantes, wiretap, wiretapping

Secret Police >> S Words
Secret Police, definition of term: Secret Police
secret+police_pag1.html

Police >> P Words
Police, definition of term: Police
police_pag1.html

Secret >> S Words
Secret, definition of term: Secret
secret_pag1.html

Secret Service >> S Words
Secret Service, definition of term: Secret Service
secret+service_pag1.html

Police Power >> P Words
Police Power, definition of term: Police Power
police+power_pag1.html

Police Departme >> P Words
Police Departme, definition of term: Police Departme
police+departme_pag1.html

Police Jury >> P Words
Police Jury, definition of term: Police Jury
police+jury_pag1.html

Police Officer >> P Words
Police Officer, definition of term: Police Officer
police+officer_pag1.html

Trade Secret >> T Words
Trade Secret, definition of term: Trade Secret
trade+secret_pag1.html