The worst post office massacre took place on 20 August 1986, at Edmond, Oklahoma.

Patrick ‘Sandy’ Sherill, a forty-four-year-old part-time postal worker attached to the main post office in this suburb of Oklahoma County, had been warned the day before his killing spree that he was facing a dismissal for unsatisfactory work. It was not the first time Sherill had been in trouble, and reports from the postal authorities claimed that he had already been under suspension once in the year since he joined as a postman in 1985.

Sherill was always prepared to tell anybody that with an inclination to listen that he was a Vietnam veteran, which was quite untrue. However, he was a member of the Oklahoma National Guard, and a considerable marksman with their competition team. In this position of trust, Pat Sherill was able to withdraw guns from the ONG arsenal for the purpose of entering shooting competitions, and on 5 April 1986 he borrowed a .45-calibre automatic pistol. On 10 August he borrowed another, identical, weapon and three hundred rounds of ammunition.

On the hot Wednesday morning of 20 August, Patrick Sherill, wearing his regulation postman’s uniform, drove to work as usual, taking with him the two .45s plus his own .22-calibre handgun and the ammunition. He walked towards the post office, stopping just once to shoot dead a fellow-worker who was crossing the car park, before passing through the employees’ entrance into the single storey building. After locking several doors in order to maximise his kill, Sherill began, in the words of the police, ‘shooting people as though they were sitting ducks’. Although FBI marksmen were deployed around the building after an employee escaped and raised the alarm, Sherill refused to speak to the specially trained siege negotiators.

When the police eventually stormed the building they found the bodies of fourteen men and women, and seven other badly wounded victims. Patrick Sherill lay dead where he had put a single bullet through his own head, his arsenal of guns and ammunition beside him.