The skeletal remains of a man were found in a building that has been vacant for at least 35 years, authorities said on Tuesday.

Police believe a homeless man entered the former Patterson Police Department, that had been gutted by a fire in 1980, on Washington Street and accidentally locked himself in a holding cell, NBC4 reported.

A contractor found the unidentified body on Monday after Susan Greenbaum, the woman whose family owns the building, started the process of selling to a developer. 

The Paterson Police Department was destroyed by fire in February 1980 and was left boarded up and empty since.

“I’ve never seen anyone get inside. I don’t think there’s access for anyone to get inside. If there’s a body there then it had to be there before I was even born,” Alvonesha Brown, who works next door, told CBS2. “It’s interesting. I would like to know who it is and the story behind what happened here.”

Police think the man died about eight to 10 years ago based on a water bottle and over-the-counter medication found near him in the cell, Greenbaum told NBC4.

"The deceased has not been identified and information regarding his identity will not be released at this time," Paterson Police Captain Richard Reyes said, NJ.com reported.

"It's tragic and we are upset about it," Greenbaum said, NBC4 reported. "My family was born and raised in this community, and we have a great respect for the community. It's sad that we have a homeless problem."