The break-in was carried out by Vietnam War veterans Art Franklin, Gene Delgado, and John Rourke, though it was masterminded by Eleanor Wish. Franklin and Delgado tunneled under the building during the weeks leading up to Memorial Day weekend, setting off the Bank's alarm in the process. Their intended target was the security box of Nguyen Tran, which was known to contain roughly $18-million in diamonds. Having discovered the nature of the September 1991 break-in at the WestLand National Bank based on his investigation into the murder of Billy Meadows, LAPD detective Harry Bosch determined that the Safe & Lock would be the next target of the WestLand robbers.
Rourke, an agent with the FBI, set up a surveillance team on the building, but instructed officers not to intervene. Bosch, however, was being monitored by LAPD IAD detectives Don Clarke and Pierce Lewis, who believed that Bosch that somehow involved in the attempted robbery. When the manager of the Safe & Lock, Martin V. Avery III, was called out on an alarm, the two IAD detectives intercepted him and made him open the vault, interrupting the robbery in progress. Clarke and Lewis were killed by Franklin, who fled with Delgado back into their entry tunnel in an attempt to escape.
The two were pursued by Bosch, who shot and killed Franklin and was shot by Delgado before Delgado was shot by Agent Rourke. Bosch nearly bled to death before Rourke attempted to kill him, but Rourke was shot and killed himself by Agent Wish.