The original tip was placed by Donald “Tony The Greek” Frankos in 1989 and discredited by investigators. NYDailyNews.com explains further:
As Frankos described it, mob leaders tried to dissuade Hoffa from retaking control of the Teamsters after his release from prison on a jury tampering rap. But Hoffa refused, and allegedly threatened to tell authorities about mob infiltration of the unions.
Hoffa was last seen in a restaurant parking lot outside Detroit on July 30, 1975. Frankos claimed Hoffa was killed in Michigan by members of the Westies, a New York Irish gang, on the orders of Genovese crime family boss Anthony “Fat Tony” Salerno.
His body was cut up in Michigan, then driven to New Jersey several months later and buried in the concrete foundation of the sprouting Giants Stadium, Frankos said. He even claimed to know what area of the stadium: Section 107, in the corner of the west end zone.