Mummified human remains were found during a search last week of the residence of a 53-year-old North Jersey man charged with sexually assaulting a child, authorities announced Friday.

Robert Frank Williams was charged with first-degree aggravated sexual assault and related offenses, as well as second-degree desecration of human remains, said Acting Essex County Prosecutor Theodore N. Stephens II and Newark Public Safety Director Anthony Ambrose in a news release.

An investigation of Williams was launched after Newark police were told that a 13-year-old child was sexually assaulted by Williams over several months starting in 2018.

On Thursday, Stephens and Ambrose said, detectives executed a search of his residence and “found mummified human remains in a bin in a closet” and “an alter to an unknown deity in his bedroom.”

The investigation was ongoing. No further details were released.