No clear answers as to what caused Russian jet crash

U.S. intelligence sources tell CBS News a missile or rocket propelled grenade likely did not bring down the Russian jetliner over Egypt. They are not ruling out a bomb inside the plane. The disaster Saturday killed all 224 people aboard. Emergency workers are combing the crash site for more victims and clues. The Airbus plane went down over Egypt's Sinai Peninsula, about 23 minutes after takeoff from Sharm el-Sheikh. Allen Pizzey reports from Cairo.