Conversation, The (1974)
Plot:
A routine wiretapping job turns into a nightmare when Harry, an expert surveillance man, hears something disturbing in his recording of a young couple in a park. His investigation of the tape and how it might be used sends Harry spiraling into a web of secrecy, murder and paranoia.
Director:Francis Ford Coppola
Starring:Harrison Ford, Robert Duvall, Gene Hackman, Allen Garfield, Cindy Williams, Teri Garr, Frederic Forrest, John Cazale