A FedEx worker was found dead at a delivery hub in Illinois Thursday morning. Police believe weather could have been a factor in the man's death, WQAD reported.

WGN said the temperatures were below zero.

The 69-year-old worker was found between two semi tractors by another employee, police said.

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Police said they are not sure how long the man was there before he was discovered, and there's no sign of foul play, WQAD reported.

But police said the cause of death was not known. An autopsy is scheduled for Monday, according to WQAD.

"It appears to be a medical issue or natural, but we won't know if the frigid temperatures played a part until after the autopsy," coroner Brian Gustafson told the Quad Cities Times.

Police are reviewing security cameras around the location, WQAD reported.