[3] At approximately 4 a.m on Sunday, June 16, 1991 – Father's Day – an alarm went off in a basement storage room at the United Bank Tower.

There, the gunman forced two guards, Phillip Mankoff and Scott McCarthy, into a battery room, where both men were shot and killed.

[5][page needed] Upon investigation, police determined the shooter fired eighteen shots during the killing spree, hitting his victims with all except one of them.

[7] Before leaving the guard room and entering the vault area, the intruder removed and tampered with evidence so as to eliminate any trace of his identity.

The perpetrator seized ten videotapes, bank keys, a two-way radio, and pages of the guard logbook.

He ordered the senior vault manager, David Barranco, to fill a satchel with cash from the work stations.

[5][page needed] Prior to leaving the scene, the robber collected all the spent shell casings that had been removed from his revolver after firing it.

After retiring from the Denver Police Department in 1986, King worked as a part-time guard at the bank between 1989 and 1990, leaving the job ten months before the robbery.

King and his wife had declared bankruptcy a year after he retired from the force, and still had substantial debt in 1991, including $25,000 in credit card bills.

The only suspicious things found were a detailed map of the bank building interior in a folder marked "plans", and five phony ID cards, containing King's picture with different aliases.

[7] These phony ID cards would be suppressed by a judge and not included as evidence in his trial, on grounds that it was never established King had ever used them in any illegal activity, nor could they be connected in any way to the robbery and murders.

After the trial, the FBI kept King under observation for years, hoping to find something they could charge him with that was not prevented by double jeopardy procedure, but they found nothing.