Authorities say an 18-year-old man planned to attack churches in a northern Idaho city using a metal pipe, butane fuel, a machete and potentially his father’s guns. Alexander Scott Mercurio has been charged with attempting to provide material support to the Islamic State group. He was arrested Saturday, and the charges were unsealed Monday in federal court. Investigators say Mercurio adopted the Muslim faith against his Christian parents’ wishes and was in contact with FBI informants posing as Islamic State group supporters. Phone messages left for a relative and for the federal public defender's office were not immediately returned Tuesday.