Government Investigations

The President's Commission on the Assassination of President Kennedy received the FBI's first frame-by-frame study of the film in December 1963. Commission staff used the film to establish the timing of the shots, working backward from the FBI's measurement of the camera's 18.3 frames per second.

The Commission's September 1964 report concluded that Lee Harvey Oswald, firing from the sixth-floor southeast corner window of the Texas School Book Depository, fired all of the shots that struck the President and Governor Connally. The Zapruder film was used to place the first shot between frames Z-210 and Z-225 and the fatal shot at Z-313 (Warren Report, ch. III).

The Commission on CIA Activities within the United States, chaired by Vice President Rockefeller, examined a small set of assassination questions in 1975 after ABC's televised broadcast of the film. It concluded that the head snap visible at Z-313 through Z-320 was consistent with a shot from behind, based on a neuromuscular reaction theory advanced by Dr. Alfred Olivier. This finding was later criticized by the HSCA photographic panel as inconclusive.

The HSCA convened a Photographic Evidence Panel of 22 professional photo-analysts, chaired by Robert Groden and Calvin McCamy. Working with an inter-negative of the camera-original held by Life, the panel authenticated the film as unaltered and consistent with the Nix, Muchmore, and Bronson films of the same event (HSCA Report, vol. 6).

The Committee's headline conclusion — that Kennedy was "probably assassinated as a result of a conspiracy" — did not rest on the Zapruder film. It rested on the acoustic analysis of a Dallas Police Department dictabelt recording, which the Committee's experts interpreted as showing a fourth shot from the grassy knoll. The National Academy of Sciences' Ramsey Panel (1982) subsequently rejected that acoustic analysis, and the FBI's 1988 review concurred. The acoustic finding is no longer accepted by the mainstream scientific community; the HSCA's photographic authentication of the Zapruder film remains uncontested by any federal body.

Created by the JFK Records Act of 1992, the ARRB was an independent civilian board with subpoena power. Its mandate was records declassification, not re-investigation of the crime. In the course of its work it commissioned Kodak senior scientist Roland Zavada to conduct a formal technical study of the camera-original.

Zavada's 1998 report concluded that the film held by NARA is an in-camera original — a first-generation Kodachrome II 8mm reversal exposed in a Bell & Howell Zoomatic — and shows the physical characteristics (edge print, splice patterns, perforations) expected of that stock and camera. Zavada found no evidence of alteration (Zavada Report, 1998).

Separately, the ARRB took depositions from NPIC analysts Homer McMahon and Ben Hunter, who described briefings at the CIA's photographic center on the weekend after the assassination. Those depositions are the primary basis for the modern alteration hypothesis advanced by ARRB staff member Doug Horne — a hypothesis Zavada explicitly rejected in a 2009 addendum, and one the ARRB itself did not endorse.

As a matter of formal federal finding, the film is authentic and unaltered (Warren Commission, HSCA, ARRB/Zavada). The identity of the shooter or shooters is contested only insofar as the HSCA's acoustic-based conspiracy finding was subsequently overturned by peer review. The 2017–2023 tranches released under the JFK Records Act have not produced any document that contradicts the authentication of the film itself.