Federal authorities have found several concrete slabs in a suburban Detroit field where they are searching for the remains of Jimmy Hoffa, sources tell NBC 4 New York.
The findings are significant because a Mafia captain's tip that led to the renewed search said Hoffa was buried beneath a concrete slab in the area.
Tony Zerilli told NBC 4 New York exclusively earlier this year that he knew the location of Hoffa's remains. He was in prison at the time of Hoffa's disappearance, but says he was told after his release about where Hoffa was buried.
He sat down again with NBC 4 New York Monday, satisfied that FBI agents appeared to finally be taking his story seriously.
"I'm glad to see it. I'm glad to hear it," said Zerilli, who has written a book about his experience. "Now everyone will know what I told them is what happened."
Authorities are using heavy machinery and cadaver dogs, and are also digging by hand.
Law enforcement sources said Zerilli, who was second in command of Detroit's mob family when Hoffa disappeared, is the most credible person to speak since Hoffa disappeared in July 1975.
Hoffa, Teamsters president from 1957-71, was an acquaintance of mobsters and an adversary of federal officials. The day in 1975 when he disappeared from a Detroit-area restaurant, he was supposed to be meeting with a New Jersey Teamsters boss and a Detroit Mafia captain.
Since then, multiple leads to his remains have turned out to be red herrings.
In September, police took soil from a suburban backyard after a tip Hoffa had been buried there. It was just one of many fruitless searches. Previous tips led police to a horse farm northwest of Detroit in 2006, a Detroit home in 2004 and a backyard pool two hours north of the city in 2003.