An Iranian nuclear scientist who American officials say defected to the United States and then had second thoughts was given a hero’s welcome when he returned to Tehran early Thursday morning. The scientist, Shahram Amiri, 32, added details to his claims that he had been abducted by the C.I.A. and Saudi intelligence. A wreath of flowers was placed around his neck as he was greeted at Imam Khomeini International Airport by family members, including his 7-year old son, red-eyed from crying, and a grinning foreign Ministry official.
