The chief of the terrorist group Hizbul Muhajideen was killed in an encounter on the outskirts of Srinagar on Sunday, the police said, calling it "a major success against militancy". Saifullah, who had taken command of the outfit after the killing of Riyaz Naikoo in May this year, was one of the most wanted terrorists in the Jammu and Kashmir and was involved in several attacks on the security forces, an official said.