The number of possible killers grew and grew, as investigators probed their underworld connections and bargained with convicts who were willing to dish the dirt in exchange for a reduction in their sentences.
Between January 1976 and February 1977 the United States government issued internal reports which were based on interviews with an informer who claimed to know the entire story of Hoffa's disappearance. The informer, Ralph Picardo was serving a sentence for murder at Trenton State Prison in New Jersey. In 1975 Picardo was a driver for 'Tony Pro' Provenzano and he revealed that Hoffa had been invited to the restaurant meeting by renowned Detoriot mobster, Anthony Giacalone for a 'sit down' with Provenzano to make amends over their differences.
O'Brien, who claimed to have been on a fish-carving expedition that day, had, according to Picardo, picked up Hoffa at the restaurant and driven him to a nearby house where Teamster business agent Thomas Andretta, Salvatore Briguglio and his brother Gabriel waited to ambush Hoffa. Frank Sheeran was also present.
Picardo claimed that the hit had been ordered by Pennsylvania mob boss Russell Bufalino, because his cousin, William, had a big falling out with Hoffa in 1967, and Bufalino had passed the actual deed of murder onto Provenzano.
Bufalino's exact whereabouts on the day Hoffa was murdered were never confirmed but the FBI believed there was little doubt that Hoffa was murdered, as Picardo had confessed.
In 1985 the FBI released a memo summarising citing, Briguglio along with brother Gabriel, Andretta, O'Brien, Provenzano, Giacalone and Bufalino as their prime suspect for Hoffa's murder. Without a body or circumstantial evidence that will hold up in court, there will probably never be a conviction in the case of Hoffa's disappearance. While the so-called conspirators could not be charged, over the years the United States government ensured the men were prosecuted to the full extent of the law on countless other charges.
Provenzano's pocket local, Local 560, eventually came under government oversight, putting a major crimp in his illegal operations. In 1978 he was prosecuted and found guilty of the 1961 murder of Anthony Castellito. A full 17 years after Castellito's body was allegedly put through a tree shredder, he was sent to prison where he died 10 years later at the age of 81.
Giacalone was tried and convicted on tax evasion charges in 1976 and spent 10 years in prison. He was also charged with racketeering, or operating an illegal business for profit, violations in 1996, but died before the case could be tried.
Despite numerous holes in O'Brien's alibi, he was never charged with Hoffa's disappearance. O'Brien moved to Florida where he was given a job by Teamster president Frank Fitzsimmons but was banished from the union in 1990 for his mob connections. Plagued with ill-health, O'Brien has survived cancer and four heart bypass operations and now lives in Florida where he maintains that the government, not the mob, killed Hoffa.
Briguglio was murdered in New York in 1978. At the time, he had been talking with prosecutors and was about to make a deal in exchange for his testimony against Provenzano in the Castellito murder case.