A District man who allegedly took a 15-year-old girl across state lines with the intent that she engage in prostitution was indicted Wednesday, authorities said.

Melvin Douglas, 31, was indicted in federal court in Greenbelt for allegedly committing the offense between Sept. 5 and Feb. 9, according to the U.S. Attorney's Office. If convicted, he could receive a sentence of up to life in prison.

Authorities said the Maryland Child Exploitation Task Force found an advertisement for a missing Prince William County girl on a website that is often used to post advertisements for prostitution and escort services.

A "date" was set up with the girl, and an undercover Maryland State Police officer was told to meet the victim at a designated motel room in College Park. Members of the task force found the victim at the room, authorities said.

Before the undercover officer arrived at the motel, an FBI special agent saw Douglas and another woman near the room. Douglas and the woman were arrested, authorities said.

A search of Douglas' car revealed a receipt for the telephone that was the contact phone in the advertisement for the girl on the website, authorities said. A search of the victim's phone turned up text messages to Douglas and pictures of the girl and Douglas together.

Douglas, who is also known as Melvin Longwood, is being detained on related state charges.