Jimmy Hoffa Agreement. He played a major role in the growth and development of the union, which eventually became the largest (by membership) in the United States with over 2.3 million members at its peak, during his terms as its leader. Hoffa became involved with organized crime from the early years of his Teamsters work, and this connection continued until his disappearance in 1975. He was convicted of jury tampering, attempted bribery and fraud in 1964, in two separate trials. He was imprisoned in 1967 and sentenced to 13 years. In mid-1971, he resigned as president of the union as part of
Jimmy Hoffa assaulted. The threats from the mafia that they would get rid of Hoffa were taken very seriously; Hoffa's son is quoted as saying "Dad was pushing so hard to get back in office, I was increasingly afraid that the mob would do something about it." There had been three visits in a short time frame to Hoffa's home at Lake Orion and one trip to the Guardian Building law offices by Anthony Giacalone, an alleged kingpin in the Detroit Mafia, and his younger brother, Vito. Friendly with Provenzano and believed to be related to him, their avowed purpose in coming