Dunbar Armored robbery
The Dunbar Armored robbery is the largest cash robbery to have occurred in the United States. It occurred in 1997 at the Dunbar Armored facility in Los Angeles, California. The thieves made off with some US$18.9 million  ($28.8 million today).
The robbery was masterminded by Allen Pace, who worked for Dunbar as a regional safety inspector. While on the job, Pace had time to photograph and examine the company's Los Angeles armored car depot. He recruited five of his childhood friends, and on the night of Friday, September 12, 1997, Pace used his keys to gain admittance to the facility. Pace had timed the security cameras and determined how they could be avoided. Once inside, they waited within the staff cafeteria, ambushing the guards one by one, who were having a break every night at exactly 12:30 AM.
Pace knew that on Friday nights the vault was open due to the large quantities of money being moved. Rushing the vault guards, the robbers managed to subdue them before they could signal any alarms. In half an hour, the robbers had loaded millions of dollars into a waiting U-Haul. Pace knew exactly which bags contained the highest denomination and non-sequential bills. He also knew where the recording devices for the security cameras were located and took these.
The police immediately realized it was an inside job and closely examined Pace, but could find nothing. The gang worked hard to conceal their new wealth, laundering it through property deals and phony businesses. Eventually, one of the gang members, Eugene Lamar Hill, erred when he gave a friend, who was a real estate broker, a stack of bills still wrapped with the original cash straps. The associate went to the police, leading to the arrest of Hill, who soon confessed and named his associates. Allen Pace was arrested and sentenced to twenty-four years in prison. Less than half (5 million) of the money was ever recovered, with some US$13.9 million still unaccounted for.
3. Deans, Andrew (7 April 2017). "Price of greed" - The FBI Files.