Jimmy Hoffa Disappearance: The Inside Story of the Crooked Teamster Boss Knew Too Much (FPD CASE VAULT)

The shocking disappearance of mobbed-up Teamster boss Jimmy Hoffa is still unsolved more than 38 years after he headed out to meet two gangland chieftains and never returned.

The Feds have poured more than $3 million into an intense search to find his body. They've come up empty after a series of wild goose chases. But most investigators believe Hoffa was killed by organized crime czars who feared he knew too much.

The 62-year-old labor kingpin, who did time for jury tampering, attempted bribery and fraud, was last seen on July 30, 1975, at the Machus Red Fox restaurant near Detroit.

Hoffa was supposed to meet two Mafia bigwigs: Detroit crime lieutenant Anthony "Tony Jack" Giacalone and New Jersey capo Anthony "Tony Pro" Provenzano.

"When Hoffa didn't return home that evening, his wife reported him missing," says a source. "Police found Hoffa's car at the restaurant, but there was no sign of Hoffa himself or any indication of what happened to him."

The search for Hoffa's body began about two months after he vanished. It has resulted in lawmen digging up empty fields and demolishing barns. And it continues to this day.

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In June, investigators searched for his remains in a Detroit, Mich., field without success.

Admitted underworld hit man Donald "Tony the Greek" Frankos insists Hoffa was buried under Giants Stadium in East Rutherford, N.J. Agents found no evidence to support the claim.

Hoffa was declared "presumed dead" seven years after he disappeared.