An 18-year-old in Idaho allegedly planned a violent rampage of local churches, after he pledged loyalty to the Islamic State (IS) group. Alexander Mercurio was arrested on Saturday, one day before prosecutors say he intended to attack churches with guns,"flame-covered weapons", explosives, knives and a pipe. He allegedly wanted to move from church to church until being killed, the justice department said. He could face up to 20 years in prison.