According to the affidavit of probable cause, Hareford met Savanna Marie MacMullett via an online chat. After numerous conversations, it said, Hareford hitch-hiked from his home in Virginia to meet her.
Hareford "took advantage of his victim who was clearly only a 13-year-old girl," it said.
"He solicited her online knowing she was a 13-year- old," said county District Attorney Jack Whelan in an interview Monday. Whelan said authorities are looking into whether Hareford engaged in similar behavior elsewhere.
He was ordered held on $1 million cash bail at his arraignment.
When Hareford was arrested last week the girl was with him, and she was placed in the custody of the Washington, D.C., Child Protection Services.
The girl told police that she and Hareford had planned to run away to her mother's residence in Myrtle Beach, S.C.
She said she met Hareford about a month earlier through an online chat application called PIMD -- Party in My Dorm. She said she knew that Hareford was 20 because he had told her.
The two were found in Washingon about 7 p.m. Dec. 2 after police received an anonymous tip following news reports about the missing blond-blue-eyed teenager.
The girl's father, Thomas MacMullett, had made a public plea for her to return, saying was not angry at his daughter. "I just want her to come home," he said.
Hareford's address was listed as Grottoes, Va., in the affidavit.
In addition to sexual assault, he was charged on several other coutns, including indecent exposure.
Editor's Note: The Inquirer normally does not name victims of sexual assault. In this instance, the girl's name had been widely circulated after she was reported missing by police and by her father.
Contact Rita Giordano at 610-627-2649, firstname.lastname@example.org or on Twitter @ritagiordano.