TAMPA Fla. (Reuters) - Two men hired to clean out a Florida rental house thought they found a mannequin hanging in the garage so they cut down what they believed to be a Halloween-style prank and took it to a landfill.

But workers at the dump in west-central Florida grew suspicious of its foul odor on Thursday and called authorities, who determined the workers had actually brought in a dead man in a "mummified state," said Denise Moloney, a spokeswoman for the Hernando County Sheriff's Office.

After interviewing the workers, detectives decided they were telling the truth and not trying to cover up foul play.

"He was laying right on top of all the garbage," in the bed of a pickup truck, Moloney said. "Anyone trying to hide a body, or trying to dispose of a dead body, would probably not do that.

"It is very unbelievable," she said.

Authorities believe the dead man, Jeremy Witfoth, 33, had hanged himself within the past several weeks. An autopsy is being conducted to determine the cause of death.

(Reporting by Letitia Stein; Editing by Bill Trott)