The FBI has arrested an 18-year-old in Idaho after uncovering his “truly horrific” and “violent plot” to attack churches in Coeur d’Alene this past weekend on behalf of ISIS, the Justice Department says. 

Alexander Mercurio is now facing a federal charge of attempting to provide material support or resources to a designated foreign terrorist organization after the FBI says he devised a plan to “incapacitate his father, restrain him using handcuffs, and steal his firearms to use for maximum casualties” in an attack he had been planning to carry out in the northern Idaho resort city on Sunday, April 7. 

“The defendant allegedly pledged loyalty to ISIS and sought to attack people attending churches in Idaho, a truly horrific plan which was detected and thwarted by the FBI’s Joint Terrorism Task Force,” FBI Director Christopher Wray said in a statement. 

“The Justice Department will continue to relentlessly pursue, disrupt, and hold accountable those who would commit acts of terrorism against the people and interests of the United States,” added Attorney General Merrick Garland. 

A masked Islamic State soldier poses holding the ISIS flag in 2015. FBI investigators say Mercurio “discussed traveling from the United States to join ISIS.” (Pictures from History/Universal Images Group via Getty Images)

The FBI investigator also said Mercurio “made a ba’yah statement, pledging his allegiance to ISIS and stating his intention to die while killing others on behalf of ISIS.” 

But on Saturday afternoon, FBI agents carried out a search warrant at Mercurio’s house and took him into custody while allegedly finding items linked to the plot, including a “metal pipe,” “a black Smith and Wesson fixed blade knife” and a “machete,” according to the complaint. 

ISIS has long waged a recruitment and propaganda war online. (Reuters)

Mercurio now faces up to 20 years in federal prison if convicted on the federal charge.