Jimmy Hoffa a result of Hoffa's work with other union leaders to consolidate local union trucker groups into regional sections, and then into a national body — work that Hoffa ultimately completed over a period of two decades — membership grew to 170,000 members by 1936. Three years later, there were 420,000. The number grew steadily during World War II and through the post-war boom to top a million members by 1951. The Teamsters organized truck drivers and warehousemen, first throughout the Midwest, then nationwide. Hoffa played a major role in the union's skillful use of "quickie strikes", secondary boycotts, and other
Jimmy Hoffa caused by the 1975 disappearance of her husband, because her health had declined steadily since then. She is entombed in Michigan. In 1989, Kenneth Walton, the head of the FBI's Detroit office, told "The Detroit News" that he knew what happened to Hoffa. "I'm comfortable I know who did it, but it's never going to be prosecuted because ... we would have to divulge informants, confidential sources." In 2001, the FBI matched DNA from Hoffa's hair—taken from a brush—with a strand of hair found in a 1975 Mercury Marquis Brougham driven by longtime friend Charles "Chuckie" O'Brien on July 30,