Mr. Spann was killed after questioning Mr. Lindh, though the government offered no evidence that Mr. Lindh had participated in the revolt. At trial, he pleaded guilty to charges of providing support to the Taliban and carrying a rifle and grenade.Johnny Spann, Mr. Spann’s father, remains disappointed in the outcome of Mr. Lindh’s trial.“We’ve got a traitor that was given 20 years and I can’t do anything about it,” Mr. Spann, a real estate dealer in Winfield, Ala., previously said to The Times. “He was given a 20-year sentence when it should’ve been life in prison.”Under the conditions of his release, Mr. Lindh is barred from owning an internet-connected device without permission from the probation office. He is also barred, unless otherwise approved, from any online communications not in English and may not communicate with any known extremists.Mr. Lindh is prohibited from owning a passport and from international travel, too, a ban that prevents the immediate possibility of a move to Ireland. Mr. Lindh obtained Irish citizenship through his grandmother while in prison.Under the terms of his release, he must also undergo mental health counseling.At his sentencing in late 2002, Mr. Lindh said that he condemned “terrorism on every level, unequivocally” and had made a mistake in joining the Taliban. But assessments in recent years suggest that he may not have fully rejected extremist views.A 2017 report by the National Counterterrorism Center, first published by Foreign Policy magazine, said that as of the previous year, Mr. Lindh had “continued to advocate for global jihad and to write and translate violent extremist texts.”Another 2017 assessment, from the Bureau of Prisons, said he had made supportive statements about the Islamic State.