In 2004, Mehanna spent two weeks in Yemen, where prosecutors proved that he tried but failed to seek out training in a militant training camp, with the aim of going to Iraq fighting with Iraqis against the US-led invasion and occupation. When he returned to the US, Mehanna began to translate and post online materials described by prosecutors as Al-Qaeda propaganda. Mehanna has said that he supports the right of Muslims to defend themselves. His lawyers argued that his internet activities were protected under the U.S. First Amendment.