Since laundering money for the CIA was going so well, Deak figured he might as well do the same for organized crime. His company made huge profits moving dodgy money for everyone from the Macau triads to the Argentinean mob. We've previously covered his operation smuggling bribe money for Lockheed, which led to the fall of the Japanese government and a porn star flying a plane into a Yakuza don's house (Japanese politics are very complicated).
Deak's good times came to an end in 1984, when the U.S. Treasury publicly accused him of laundering millions for Colombian drug cartels. This prompted every spy and goon in the world to ditch his bank before the ensuing investigation revealed all their spying/goonery. Unable to meet the demand for withdrawals, Deak was forced to file for bankruptcy, probably thinking things couldn't get any worse. Then Lang and her .38 showed up.
Lang claimed that "friends" had taught her to shoot and told her she "could carry" the gun. Deak's successor as CEO unearthed evidence that Lang met with two Argentinian men in Miami immediately before buying the gun and a bus ticket to New York. He also found an unreleased photo of Deak dying in the firm's mysteriously abandoned Macau office. Oh, and it turned out Lang's old psychiatrist was associated with the Stanford Research Institute, where the CIA studied (among many other X-Files-sounding things) methods of brainwashing and mind control.