The authorities arrested a Las Vegas man who discussed attacking a local synagogue and charged him on Friday in connection with bomb-making materials found in his home, officials said.
The man, Conor Climo, was charged on Thursday with one count of possession of an unregistered firearm, namely, the component parts of a destructive device, the Department of Justice said in a statement.
Prosecutors said that Mr. Climo, 23, had communicated with people who identify with a white supremacist extremist organization, and had encrypted online conversations in which he regularly used derogatory racial, anti-Semitic and homophobic slurs.
He discussed attacking a Las Vegas synagogue, making Molotov cocktails and improvising explosive devices, officials said. Mr. Climo also discussed conducting surveillance on a bar he believed served the lesbian, gay, bisexual and transgender community in downtown Las Vegas.
During the execution of a search warrant on Thursday, the authorities seized a notebook with hand-drawn schematics for a potential Las Vegas-area attack. Also inside the notebook were drawings of timed explosive devices, the statement said.
The authorities said Mr. Climo tried unsuccessfully to recruit a person who was homeless to conduct surveillance on a local synagogue and other targets leading up to an attack.
Officials said Mr. Climo was a security guard but did not say where. His LinkedIn account showed he worked for Allied Universal, a company based in Santa Ana, Calif. Vanessa Showalter, public relations manager for the company, said Mr. Climo had been suspended.
“Threats of violence motivated by hate and intended to intimidate or coerce our faith-based and L.G.B.T.Q. communities have no place in this country,” said Nicholas A. Trutanich, the United States attorney for the District of Nevada.
If convicted, Mr. Climo faces up to 10 years in prison. It was not immediately clear if he had a lawyer.
In 2016, Mr. Climo made headlines when he announced plans to become a one-man neighborhood watch organization. In a segment on KTNV, he was seen patrolling his neighborhood with an assault rifle and four 30-round magazines. He quickly abandoned those plans.
The arrest against Mr. Climo comes against a backdrop of incendiary rhetoric, heightened threats and violence against Jews and minorities.
A study by the Kantor Center for the Study of Contemporary European Jewry said the number of major violent anti-Semitic incidents rose 13 percent to 387 in 2018. The study, which was released in May, said the United States had the highest number of cases, with more than 100, followed by the United Kingdom with 68.
The study found that a feeling of insecurity was prevalent among Jews who said that they sometimes sensed they were facing a state of emergency.
In October 2018, a gunman who shouted anti-Semitic slurs opened fire inside a Pittsburgh synagogue, killing 11 and wounding six.
In April 2019, a gunman stormed into a Poway, Calif., synagogue and screamed that Jews were ruining the world. He killed one person and wounded three others, officials said.