Conor Climo, 23, was charged with one count of possession of an unregistered firearm, “namely, the component parts of a destructive device,” the Department of Justice said Friday.
Court documents show that Climo communicated via an encrypted internet chatroom with people identified as white supremacists and told an FBI informant on the chat that he was scouting for places to attack.
“Threats of violence motivated by hate and intended to intimidate or coerce our faith-based and LGBTQ communities have no place in this country," U.S. Attorney Nicholas Trutanich said in a statement.
The complaint also alleges that Climo would regularly use derogatory racial, anti-Semitic and homosexual slurs in the online conversations and would discuss attacking a Las Vegas synagogue and making Molotov cocktails or other improvised explosive devices.
The documents also point to a 2016 news report by KTNV-TV about Climo patrolling his neighborhood wearing battle gear and carrying an assault rifle and survival knife. He shows and describes to a reporter the four 30-bullet ammunition magazines he is carrying.
Neighbors expressed concern, but Climo was not arrested at the time. Nevada is an open-carry state, and Climo broke no laws, officials said Friday.
The U.S. attorney said Friday that Climo was arrested Thursday after an investigation involving at least one undercover online contact and an FBI confidential informant.
When he was arrested, authorities found hand-drawn schematics and component parts of a destructive device, including flammable liquids, oxidizing agents and circuit boards. They also confiscated an AR-15 assault-style weapon and a bolt-action rifle.
U.S. Sen. Jacky Rosen, D-Nevada, tweeted after the arrest was announced saying: “I’m grateful that our law enforcement was able to act quickly and prevent this from becoming a tragedy.”
"Hate and bigotry have no place in our communities," she said.
Climo was ordered to remain in federal custody pending an Aug. 23 court appearance on the federal firearms charge. He faces up to 10 years in prison and a $250,000 fine if he is convicted.
The arrest comes less than a week after a gunman who allegedly confessed to police that he was targeting people of Mexican descent opened fire at an El Paso Walmart, killing 22 people.
The Associated Press contributed to this report.