JACKSONVILLE, Fla. -- A federal jury has convicted a man of two counts of sex trafficking of minors and one count of transporting minors across state lines for prostitution.

Federal prosecutors said Marvin Madkins, 29, of Newport News, Va., told two underage girls in Virginia that if they engaged in prostitution for a short time they would earn enough money to enjoy an extravagant vacation in Florida.

After both engaged in prostitution in Virginia, he brought them to Jacksonville last spring, where they were forced to engage in more sex acts with multiple people to earn money for lodging, food and other items.

Authorities were called when a security guard at a hotel said he found one of girls in a room with pornographic videos and photos and her friend in another room with a man.

Prosecutors said Madkins sought customers for the sex acts using various methods, including postings on Craig's List.

He was convicted Friday by a jury in Jacksonville. He faces a maximum penalty of life in prison.

U.S. District Judge Marcia Howard sentenced a sentencing hearing for June 15.