A 25-year-old St. Paul man was charged in U.S. District Court on Thursday with sex trafficking involving three teenage girls.

Dontre D'Sean McHenry was arrested in March in a Roseville motel after a Homeland Security investigator and Minneapolis police responded to an advertisement on Backpage.com, an adult-orientated website, that investigators believed featured a juvenile sex trafficking victim.

According to the charges:

When investigators arrived at the motel they found McHenry with a 17-year-old girl who admitted she was the girl in the Backpage ad. Investigators later learned that he also had prostituted a 15-year-old girl and 16-year-old girl.

McHenry is accused of exploiting and prostituting the three minors by using force, threats of force, fraud or coercion. He is accused of selling them for sex and communicating with johns via text messages and online chat rooms.

The investigation shows that McHenry ran "a sophisticated, ongoing criminal sex trafficking business," said U.S. Attorney Andy Luger.

According to the criminal complaint, Minneapolis police seized items from the motel room including the book "Pimpology," which outlines "The 48 Laws of the Game" to promote the pimp mentality and provide psychological manipulation.

Among the handwritten notes that police seized were 13 questions, including "Are u homeless? Tired of your mom/dad getting on ur nerves? Wanna move out?"

Mary Lynn Smith