Willis was present in Dealey Plaza during the assassination of Kennedy on November 22, 1963. Standing near the curb at the corner of Houston and Elm Streets, he took a series of color slides immediately before, during, and after the assassination. Willis appears in the Zapruder film until frame #206, just prior to Kennedy disappearing from view behind the Stemmons Freeway sign. During the assassination, Willis snapped a 35mm color slide showing the presidential limousine and its occupants, the United States Secret Service agents' follow-up car and occupants, parade onlookers, and the grassy knoll visible in the background.
Testimony and aftermath
On July 22, 1964, Willis provided testimony to Wesley J. Liebeler, assistant counsel of the Warren Commission, at the Post Office Building in Dallas. Twelve of Willis' color slides with descriptions served as "Willis Exhibit 1" for the Warren Commission. Willis testified to the Commission that his fifth photo was inadvertently snapped when, just after he had prepared his 35mm Argus camera to capture a photo, he was suddenly startled by a gunshot related noise, and his finger that was already on the camera shutter button reacted to the gunshot related noise, then, he quickly depressed the button and the fifth photo was captured. As documented by the House Select Committee on Assassinations, this fifth photo was captured concurrent with Zapruder film frame 202. In his fifth photo, some conspiracists allege that the image of a still-unknown person can be seen located up on the grassy knoll, seen near a 3-foot-tall concrete wall and near the 5-foot-tall stockade fence. The angled shape of this still-unknown person's outline has led to that person's image being labeled by authors in books and persons working in the Kennedy assassination research community the "black dog man." In 1978, when Willis's daughter Rosemary was interviewed by investigators from the House Select Committee on Assassinations, she stated to the HSCA that her father became upset when the Dallas policemen, sheriffs, and detectives—who first quickly ran onto the grassy knoll where Phillip thought the shots came from—then ran away from the grassy knoll. In Willis's Warren Commission testimony he stated that shots came from the Texas School Book Depository. Willis stated in a 1979 interview: "There's no doubt in our mind the final shot that blew his head off did not come from the depository. His head blew up like a halo. The brains and matter went to the left and the rear.'
Later life
On January 27, 1995, Willis died of leukemia at his home in Dallas. The Texas House passed a resolution to honor him.
