The Parallax View

The Parallax View is a 1974 American political thriller film directed and produced by Alan J. Pakula, and starring Warren Beatty, Hume Cronyn, William Daniels and Paula Prentiss. The film was adapted by David Giler, Lorenzo Semple Jr and an uncredited Robert Towne from a 1970 novel by Loren Singer. The story concerns a reporters investigation into a secretive organization, the Parallax Corporation, whose primary focus is political assassination.

TV newswoman Lee Carter Paula Prentiss is one of many witnesses to the public assassination of presidential candidate Senator Charles Carroll Bill Joyce atop the Seattle Space Needle. A waiter armed with a revolver is chased but falls to his death. Meanwhile, a second waiter, also armed, leaves the crime scene unnoticed. A Congressional special committee determines that the assassination was the work of a lone gunman.Three years later, Carter visits her former boyfriend and colleague, newspaper reporter Joe Frady Warren Beatty. Lee tells Frady that she feels there is more to the assassination than was reported at the time. Six of the witnesses to Carrolls assassination have since died, so she fears she will be next. Frady does not take her seriously. Carter is soon found dead and her death is judged by the police to be either a voluntary or accidental drug overdose. ........

Source: Wikipedia