George Hickey was born in 1923. He became a member of the Secret Service working for the White House in Washington. During the motorcade tour of Dallas on 22nd November, 1963, Hickey was in the follow-up car, directly behind the presidential limousine. When President John F. Kennedy was shot he rose to his feet with his AR-15 machine gun but did not fire it.
Winston G. Lawson claimed: "As the lead car was passing under this bridge I heard the first loud, sharp report and in more rapid succession two more sounds like gunfire. I could see persons to the left of the motorcade vehicles running away. I noticed Agent Hickey standing up in the follow-up car with the automatic weapon and first thought he had fired at someone." The following day Hickey was quick to deny he fired a shot. He issued a statement: "After a very short distance I heard a loud report which sounded like a firecracker. It appeared to come from the right and rear and seemed to me to be at ground level. I stood up and looked to my right and rear in an attempt to identify it. Nothing caught my attention except people shouting and cheering." Tim McIntyre, the Secret Service Agent standing next to him at the time also confirmed there was no shot.
The Warren Commission reported: "Special Agent George W. Hickey, Jr., in the rear seat of the Presidential follow-up car, picked up and cocked an automatic rifle as he heard the last shot. At this point the cars were speeding through the underpass and had; left the scene of the shooting, but Hickey kept the automatic weapon ready as the car raced to the hospital. Most of the other Secret Service agents in the motorcade had drawn their sidearms."
In Mortal Error: The Shot that Killed JFK, published in 1992, Bonar Menninger argues that Kennedy was killed by Hickey. He claimed that after the first shot, he stood up and lost his balance, and accidentally discharging his gun into the back of Kennedys head. According to Menninger: "Hickey reaches down and grabs the AR-15 off the floor, flips off the safety and stands up on the seat, preparing to return fire. But his footing is precarious. The follow-up car hits the brakes or speeds up. Hickey begins to swing the gun around to draw a bead on Oswald, but he loses his balance. He begins to fall. And the barrel happens to be pointing toward Kennedy's head. And the gun happens to go off."
The book was based on the following evidence: (1) S. M. Holland saw Hickey lose his balance when he stood up during the firing; (2) AR-15 rounds are encased in thin copper and tend to break up upon impact, as did the shot that struck John F. Kennedy in the head; (3) A Mannliher-Carcano bullet would not break up when it hit a target; (4) Ralph Yarborough and other witnesses smelled gunpowder soon after the shooting, indicating that at least one shot had been fired from street level; (5) Two witnesses, Austin Miller and Royce Skelton, thought one of the shots came from near the presidential limousine and (6) Howard Donahue argued that the bullet's trajectory that hit Kennedy in the head suggested it came from Hickey's gun.
In April, 1995, George Hickey sued St. Martin's Press about what was said about him in the book, Mortal Error: The Shot that Killed JFK. His lawyer, Mark S. Zaid: "We're trying to stop this now while Hickey's still alive... He doesn't want his grandchildren growing up and hearing other children say, Hey, your grandfather killed the president of the United States." According to Zaid: "We settled the case then but only if it included an apology from the publisher that would send the message to most reasonable people that the theory was flawed."
George Hickey died in 2011. Aware that he could no longer be sued, Bonar Menninger worked with Colin McLaren, a veteran Australian police detective, to make a documentary, JFK: The Smoking Gun, repeating the claims.