A missing Iranian nuclear scientist, who Tehran claims was abducted by the U.S., has taken refuge at a Pakistani embassy office in Washington and is planning to return to his homeland, the State Department said Tuesday. It was the latest development in a murky case that has been shrouded in mystery since the scientist, Shahram Amiri, disappeared while on a pilgrimage to Saudi Arabia in June 2009. "He has been in the United States of his own free will and obviously he is free to go," department spokesman P.J. Crowley said. "In fact, he was scheduled to travel to Iran...