The Sri Lanka bomb attack was a suicide bombing. According to police sources, there was an attack on hotels and churches. There also was an attack on a fourth hotel but fortunately, it failed and it even helped lead police to the Islamist group that is now being blamed for the assault.
It was the bombers' suspected mastermind, Islamist preacher Zahran Hashim who the police were lead to. He was among the 15 people killed during the raid the police conducted on a house in the eastern town of Sainthamaruthu. So, all in all, it was the Islamist group who was responsible for the bombing.