Although he didn’t show much mercy to his opponents in the ring, boxing legend Muhammad Ali has made a desperate plea to Iran’s supreme leader, Ayatollah Ali Khamenei, to release two Americans who have been held since July 2009 on suspicion of espionage, Ali’s spokeswoman said Wednesday. Shane Bauer, Josh Fattal, and Sarah Shourd were arrested along the Iraq border, claiming they accidentally crossed into Iran while hiking. Shourd was released on $500,000 bail in September and returned to the U.S., but the two men remain imprisoned. Ali asked in a letter to Iran’s supreme leader that “mercy and compassion” be shown to the two men. Bauer and Fattal pleaded not guilty on Feb. 6, and their trial is expected to start on May 11, according to an Iranian official.