Parallax View, The (1974)

After a presidential candidate is assassinated, political reporter Joe Frady (Warren Beatty) begins to suspect that the mysterious Parallax Corporation may be involved. As he investigates, others who share his suspicions start turning up dead, including his editor, Bill Rintels (Hume Cronyn). Eventually, Frady uncovers a conspiracy bigger than anyone expected and must race to prevent the corporation's next big hit as this political thriller plays out in an explosive game of cat and mouse.