COEUR d’ALENE — A man accused of planning to attack a local church on behalf of ISIS last year pleaded guilty in federal court Wednesday, according to the U.S Attorney’s Office for the District of Idaho.

Alexander S. Mercurio, 20, pleaded guilty to attempting to provide material support to a designated foreign terror organization, a crime punishable by up to 20 years in prison. 

Authorities arrested Mercurio on April 6, 2024, the day before federal prosecutors said he planned to attack people attending a church near his home in Coeur d’Alene. He planned to incapacitate people by beating them with a metal pipe, “slit their throats with a knife or machete” and then start fires inside the church, according to court records. 

Mercurio graduated from Lake City High School in 2023. He attended North Idaho College and was on the dean’s list in fall 2023. 

The FBI began monitoring Mercurio’s online activity as early as 2022, while conducting a criminal investigation into a network that uses cryptocurrency exchanges and other platforms to raise funds and launder money for foreign terrorist organizations. 

In early 2023, Mercurio “created an online repository for pro-ISIS content with the purpose of spreading the doctrine of the Islamic State,” according to the U.S. Attorney’s Office. Prosecutors said he wanted to travel overseas to support ISIS but lacked the resources to do so.

He told a source he previously “drank the Kool-Aid of white supremacy” but felt ISIS had more purpose for him, according to court records.

Mercurio communicated with ISIS supporters online, some of whom were really “confidential human sources” who reported information about Mercurio’s plans to federal investigators, court records said. 

Mercurio, who was 18 years old at the time of his arrest, told confidential sources he planned to “carry out a martyrdom operation” in Coeur d’Alene. Just before doing so, he said he wanted to donate “every last cent” in his bank account to ISIS, a sum of around $11,000. 

Prosecutors said Mercurio purchased items to support his planned attack and, days before he intended to act, he “stood before an ISIS flag holding a knife and pledged his allegiance to ISIS.” 

Mercurio is set to be sentenced Jan. 27 before Chief District Judge David C. Nye.