Suspenseful films typically leading to exposure of some concealed fact, e.g., about a crime
  • Enemy of the State - 1998 Tony Scott thriller about the NSA and the surveillance society
  • Third Man, The - 1949 British film, winner of BAFTA Best Film award, set in post WWII Vienna

Reference

Mystery film - Wikipedia, the free encyclopedia
"Mystery film is a sub-genre of the more general category of crime film. It focuses on the efforts of the detective, private investigator or amateur sleuth to solve the mysterious circumstances of a crime by means of clues, investigation, and clever deduction. ..."