“Do you know why you have come here, mother?” the man asked, reaching out for a hug. He was seated in a small room of a military barracks in Tehran, surrounded by intelligence-service agents. His mother, who had been invited by the Iranian government, was hopeful that he would be pardoned and released into the custody of his family. “I have come to see you,” she said. The man shook his head. “You have come to say goodbye.” A day or so later, his body was sent to his parents, with rope marks from his execution visible around his…