Volume IV contains the proceedings of Sept. 22, 25, and 26, 1978. The first day was taken up with the testimony of Richard Helms, former Director of the CIA. Mr. Helms was Deputy Director for Plans at the time of the JFK assassination, and was responsible for responding to requests from the Warren Commission.

The morning of Sept. 25 saw the return of handwriting expert Joseph McNally, photographic expert Sgt. Cecil Kirk, physical anthropologist Dr. Clyde Collins Snow, and photo enhancement expert Dr. Bob Hunt. The afternoon session included the interview of Louie Steven Witt, purported to be the "Umbrella Man" seen in the Zapruder film. Mr. Witt was followed by HSCA staffer Jacqueline Hess, who gave a presentation of the HSCA's analysis regarding the "mysterious deaths" issue.

The following day began with a narrative by Chief Counsel Blakey, and then continued with the testimony of Earl Ruby, brother of Jack Ruby. Mr. Ruby was followed by Capt. Jack Revill of the Dallas Police Department, who was part of the investigative team originally charged with determining how Jack Ruby had entered the police basement where he shot Oswald.