The victim was shot to death as he sat at his desk inside his office. His office safe was emptied of $4.25 million in loose diamonds and gems along with more than $250,000 in cash.
After killing the victim and cleaning out the safe, Dennes disguised himself with a baseball cap and fake mustache and went to the first floor with the intention of removing the surveillance videotape that had recorded he and his brother's entry to the building.
There he was confronted by an unarmed security guard who was shot twice and left for dead. Dennes took the tape from the surveillance camera and fled. He was arrested after a gunsmith who fashioned a silencer for the 9mm pistol Dennes used in the robbery went to police. The wounded security guard recovered to identify Dennes as the gunman.