Joshua Van Haften, 34, was arrested last night at O'Hare International Airport in Chicago after returning on a flight from Turkey. He is charged in a criminal complaint with attempting to provide material support to a foreign terrorist organization.
Van Haften was ordered held without bond during his first court appearance today.
US Attorney John Vaudreil called Van Haften a flight risk.
Van Haften's lawyer, Joseph Bugni, said he looks forward to "having all the facts brought to light."
The complaint cites Facebook posts from Van Haften that said he was unable to cross the border from Turkey into Syria.
In one post, Van Haften complained that the people who were supposed to help him just wanted his money, that he had almost no cash left and that he was dropped off on a road in the country and never picked up.
Wisconsin court records showed several previous convictions for Van Haften, including felony battery in 1998, second degree felony sexual assault in 1999 and disorderly conduct, a misdemeanor, in 2007, online court records show.
