Alexander Mercurio, 18, was arrested on Saturday by the Justice Department on charges of attempting to provide material support to ISIS after planning attacks on churches in Coeur d’Alene, Idaho.

FBI Director Christopher Wray stated that Mercurio intended to use knives, firearms, and fire for the attacks, which were thwarted by the FBI.

Court documents reveal that Mercurio’s plan involved using various weapons and explosives to carry out a suicide attack on a specific church, with intentions to incapacitate his own father to acquire guns for the attack.

Prosecutors say Mercurio pledged allegiance to ISIS and expressed his intention to die while killing others on their behalf, ABC News reported.

Law enforcement found incendiary materials and an ISIS flag during a search of his residence.

Written by B.C. Begley