TIVERTON, R.I. (WPRI) — A man suspected of bringing a 13-year-old girl from Pennsylvania to his grandparents’ home in Rhode Island to engage in sexual activity is facing new charges.

A criminal complaint filed in federal court in Providence revealed that on July 5, the minor contacted a friend on Snapchat asking for help, according to the U.S. attorney’s office.

She had tried to leave the man, William Caldwel Stewart, on at least two occasions, prosecutors allege, but he threatened to harm her with a knife.

Stewart, 20, was arrested that same day after Tiverton police found him and the girl in the basement of the High Hill Road home.

The girl was reported missing by her family on July 1. Stewart, who also lives in Pennsylvania, allegedly picked her up the previous evening and over the course of several days drove up to Rhode Island, making stops and engaging in sexual contact multiple times along the way, according to prosecutors.

The investigation revealed Stewart and the girl had talked via Snapchat before meeting in person. Prosecutors say messages obtained by Pennsylvania State Police through a court order showed the girl told Stewart she was 13 and the two discussed traveling to Rhode Island together.

Stewart allegedly bought a wig to disguise the minor prior to arriving at his grandparents’ home on July 4.

After receiving information from Pennsylvania State Police and making the arrest, Tiverton police seized a wig, a knife, and bedding from the home, prosecutors said.

Stewart is currently being held at the ACI on state charges. The federal criminal complaint additionally charges him with transportation of a minor with the intent to engage in criminal sexual activity, interstate travel with intent to engage in illicit sexual conduct, and coercion and enticement of a minor to engage in illicit sexual activity.

The incident remains under investigation.