Homeless people were found living in deep caves along a river in Central California during a recent clean-up.

Eight caves were found along the Tuolumne River in Modesto—particularly along the Crater Avenue and Dallas Street area.

The caves were about 20 feet below street level and accessible by makeshift stairs dug into the ground.

The Modesto Police Department, along with local volunteers, conducted a cleanup of the homeless encampments found nearby and inside the caves over the weekend of Jan. 20.

“This particular area has been plagued by vagrancy and illegal camps, which have raised concerns due to the fact that these camps were actually caves dug into the riverbanks,” Modesto Police said in a Jan. 23 statement on Facebook.

During the cleanup, authorities cleared 7,600 pounds of furniture and trash out of the caves—as well as two truckloads and a trailer of trash, according to the statement.

Individuals residing in the caves and at the nearby homeless camps were notified by authorities a week in advance about the clean-up operation, authorities said.

Authorities also offered various services to assist the encampment residents during the transition.

The caves have been cleared once before by authorities in 2022.

Chris Guptill, one of the local volunteers who helped clear the caves, told local news outlet CBS 13 that authorities are unsure how to keep individuals from returning to the caves once they’re cleared.

“We really don’t have a known solution on how to deal with it,” Mr. Guptill said. “It’s already been proven that people will dig these out, so I don’t think filling them in with any material would work.”

On Jan. 22, authorities put up barricades and caution tape around the mouth of the caves to keep people away.