At FCI Danbury during his marijuana trafficking sentence, March 1974, Jung's cellmate was Carlos Lehder Rivas, a young German Colombian man who introduced Jung to the dominant and powerful international drug-trafficking Medellín Cartel; in return, Jung taught Lehder about smuggling. In April 1975, when Jung and Lehder were released, they went into business together. Their plan was to fly hundreds of kilograms of cocaine from Pablo Escobar's Colombian ranch to the U.S., and Jung's California connection, Richard Barile, would take it from there. Jung had a security man who would accompany him to the exchanges, where Jung would give the man the keys to a car and half the cocaine, and then leave. A day or two later, they would meet again and exchange keys to cars.