Jan. 14, 2013 -- His body has never been found. Since Jimmy Hoffa disappeared in 1975 there have been countless tips about the whereabouts of his body, all of them dead ends. But now new information from the reputed underboss of the Detroit Mafia could lead to a break in the case.
Tony Zerilli, who the FBI believes was one of the key figures in the city's Mafia, told longtime Detroit reporter Marc Santia, now with WNBC in New York, that he believes Hoffa is buried in a vacant lot in the northern part of Oakland County, Michigan, about 30 miles from where Hoffa was last seen at The Red Fox restaurant in suburban Detroit over 37 years ago.
"The master plan… that I understood was that they were going to put him in a shallow grave here," Zerilli told Santia. "Then they were going to take him from here to Rogers City upstate. There was a hunting lodge and they were going to bury [him] in a shallow grave, then take him up there for final burial. Then, I understand… it just fell through."
Hoffa, who had headed the powerful International Brotherhood of Teamsters union, disappeared in July 1975. He was 62 and had spent nearly five years behind bars.
At the time of Hoffa's disappearance, Zerilli -- who has denied being involved in the Mafia -- was in jail. Now 85, Zerilli is releasing a book on March 1, but Dan Moldea, author of "The Hoffa Wars," says Zerilli should still be taken seriously.
"Zerilli was the underboss of the Detroit Mafia. His father Joe was the boss of the Detroit Mafia at the time Hoffa disappeared. Therefore anything that happened in Detroit at that time had to be checked by Joe -- so his father clearly knew about what happened with Hoffa. Now, Tony was in jail at the time, but did he receive some information? I'd say it was very likely, especially once he got out," Moldea told ABC News in a phone interview Monday.
"He's 85, but he sounds cogent and credible. The question is how much does he really know and how credible is what he says? He's been persona non grata in the Detroit underworld for a long time. A lot of mob guys blamed him for some information that leaked out and got some people in trouble. I guess they didn't whack him because of his father. But now, the consequence of this guy being alone and broke has made him decide to talk," Moldea said. "If he really is telling the truth about this, then I say pay him the money. His book comes out on March 1 and we'll know by then if he's telling the truth or not."
Moldea said the fact that Zerilli is talking at all is a surprise.
"The Detroit family is a very powerful family. I never even imagined that you would get one of these real families that control the Detroit mob to ever talk about this, so this is very interesting, to say the least," Moldea said. "He's either going to come out of this a national phenomenon or looking like a clown. I'm hoping that he's right."
"When you've got the underboss of the Detroit Mafia whose father was the boss of the Detroit Mafia, that's a real interesting witness," he added.
The FBI field office in Detroit declined to comment on the case, citing it as an ongoing investigation.
The new information from Zerilli is only the latest in a long line of tips in the search for Hoffa. Last September police in Roseville, about 20 miles north of Detroit, dug up a driveway. In 2009 FBI agents dug up a lumberyard in the city, prompting speculation that the excavation was a search for Hoffa. Three years earlier, in May 2006, there was a search for Hoffa at a farm in the town of Milford which became known as "The Big Dig."
None of the searches yielded anything.
ABC News' Jason Ryan contributed to this report.