Federal authorities said in the affidavit that in late March, Jalloh made his first contact with a source who was working with a now-deceased overseas co-conspirator who was a member of the Islamic State. The overseas co-conspirator encouraged the source to have an in-person meeting with Jalloh, the documents state, and when they did meet on April 9, the FBI was watching. At that meeting, Jalloh praised Mohammad Youssef Abdulazeez, who killed five U.S. service members in Chattanooga, Tenn., last year, the documents said. And Jalloh, at one point, suggested that someone known for organizing contests for cartoons of the...