From the link above, it says: "The Daulah Islamiyah-Maute Group could be behind Sunday's bombing", said Brig Gen Allan Nobleza, the police commander in the region. Gen Nobleza said 11 of its members died in an encounter with the Philippine Army last Friday in neighbouring Datu Hoffer Ampatuan town - suggesting Sunday's explosion could be a form of retaliation. Let's hope that it doesn't become a tit-for-tat situation that seems to happen with many religious differences.