So far, at least, the dirt beneath a driveway in Roseville, Mich., isn't turning up any sign that former Teamsters boss Jimmy Hoffa was buried there 37 years ago.

The first sample taken today as authorities check out the latest tip related to Hoffa's 1975 disappearance is "muddy and filled with water," Roseville Police Chief James Berlin said this morning, according to The Detroit News. "There are no visible human remains present."

The Detroit Free Press says the sample, "pulled out from six feet under a concrete slab was just a combination of clay and mud."

But the soil and another sample that's still to be collected will be tested at Michigan State University to see if there is any sign of human remains. Authorities expect initial results on Monday.

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