Robert Frank Williams (pictured), 53, has been accused of sexually assaulting a girl, 13

New Jersey police discovered mummified human remains and an altar to an unknown deity in the home of a man who has been accused of sexually assaulting a 13-year-old girl.

Robert Frank Williams, 53, of Newark, was arrested on Friday following reports that he had abused the child over several months.

The Essex County Prosecutor's Office said the abuse began in 2018.

Authorities executed a search warrant on Williams' home last Thursday.

During their search officers made the disturbing discovery of the 'mummified human remains in a bin in a closet'.

Authorities have not yet confirmed the identity of the remains and it's unclear if they are remains from an adult or a child.

No other information about the remains was provided by the prosecutor’s office.

Detectives also found 'an altar to an unknown deity' in Williams' bedroom.

Photos from Williams' Facebook show him dressed in a top hat with a red cape.

Williams, 53, of Newark, was arrested on Friday following reports that the child had been abused over several months. Authorities executed a search warrant on his home and found 'mummified human remains in a bin in a closet'

Detectives also found 'an altar to an unknown deity' in Williams' bedroom. This photo shows what is believed to be a fireplace with a mantel decorated with horns, figurines, a crystal ball and candles. It is unclear if this is the altar police described in their report

One photo appears to show dirt stuffed inside two sandwich bags.

'I collect dirts from mens and womens tombs chatholic and jewish cemetaries..as well as all required dirts to build pots..if u need specific dirts. Then i can collect any amount needed,' the photo's caption reads.

Another photo shows tombstones, mostly in the shape of crosses.

'These are some tomb stones i aquired and also for sell,' Williams wrote in the caption.

A third photo shows what appears to be a star, or hexagram, taped to the floor. These figures are used in numerous religions and for spiritual purposes.

The particular star at Williams' home had three candles near its points and knives on the inside and outside of the star, along with other objects.

This photo shows what appears to be a star, or hexagram, taped to the floor. These figures are used in some religions and for spiritual purposes

This photo appears to show dirt stuffed inside two sandwich bags. 'I collect dirts from mens and womens tombs chatholic and jewish cemetaries..as well as all required dirts to build pots..if u need specific dirts. Then i can collect any amount needed,' the photo's caption reads

This photo shows tombstones, mostly in the shape of crosses. 'These are some tomb stones i aquired and also for sell,' Williams wrote in the caption

A fourth photo shows what is believed to be a fireplace with a mantel decorated with horns, figurines, a crystal ball and candles.

Williams was hit with multiple charges that include first-degree aggravated sexual assault for engaging in an act of penetration upon a child younger than 13 years of age and endangering the welfare of a child for the production of items depicting the sexual exploitation or abuse of a child.

He was also charged with sexual assault upon a victim who was between the ages of 13 and 15, luring, endangering the welfare of a child for engaging in sexual conduct with a child, and second-degree desecration of human remains.

The investigation is ongoing.

Police are asking that anyone with information to contact the Essex County Prosecutor's Office tips line at 1-877-TIPS or 1-877-847-7432.