WASHINGTON (Reuters) -Iranian American businessman Siamak Namazi was forced to return to Tehran’s Evin prison on Wednesday after Iranian authorities had given him a furlough on Oct. 1 and let his elderly father leave Iran for medical treatment on Oct. 5, their lawyer said. Namazi, who in 2016 was convicted of espionage-related charges that the United States has rejected as baseless, on Thursday will mark seven years since his arrest and detention in Iran, a lawyer for the family, Jared Genser, said in a statement. “Yesterday, members of the Islamic Revolutionary Guard Corps (IRGC) informed Sia…