A man who was arrested in Iowa has been convicted of sex trafficking and prostitution.

Thirty-three-year-old Antoinne Lee Washington was arrested in September of last year after a woman called Urbandale police from a local hotel. Police first thought it was a case of domestic assault, but say the evidence showed Washington had been forcing the woman for several years to have sex with others for money and they called the FBI into the case. Investigators say he beat and burned the woman and threatened more violence if she did not do what he told her to do.

He was found guilty of one count of sex trafficking by force or coercion and one count of transportation for prostitution. He will be sentenced in U.S. District Court on December 5th.