KANO, Nigeria (Reuters) - Multiple bomb blasts in Nigeria's biggest northern city of Kano killed 15 people on Monday, a senior policeman said, in an area previously targeted by militant Islamist group Boko Haram. Several witnesses said they saw dead bodies after hearing multiple blasts at around 9:30 p.m. (2030 GMT) in the Sabon Gari district, a predominantly Christian area dominated by ethnic Igbos from the southeast. "In all bomb attacks 15 were killed," the policeman in Kano told Reuters, asking not to be named. ...