WASHINGTON (AP) — A man whose relatives reported concerns about his behavior and far-right extremist rhetoric after last year’s Pittsburgh synagogue massacre pleaded guilty to a federal gun charge Tuesday.

Jeffrey Clark Jr., of Washington, D.C., faces a maximum of 10 years in prison after pleading guilty to one count of illegal possession of firearms by a person who is an unlawful user of a controlled substance.

Estimated sentencing guidelines call for a sentence ranging from 10 to 16 months, but U.S. District Judge Timothy Kelly, who is scheduled to sentence Clark on Sept. 13, isn’t bound by those guidelines. The judge refused to release him before sentencing.

The FBI said Clark is a self-described white nationalist who followed Pittsburgh synagogue shooting suspect Robert Bowers on the Gab social media platform and referred to him as a “hero” in a post after the Oct. 27, 2018, shooting. Bowers spewed anti-Semitic hatred on his Gab account before killing 11 people inside the synagogue, authorities said.

Clark, then 30, was arrested after relatives called the FBI on Nov. 2 to report their concerns that he could be a danger to himself or others. Relatives told FBI agents that Clark became “really riled up” after his younger brother, Edward, shot and killed himself within hours of the Pittsburgh attack.

“After the death of Edward Clark, Jeffrey Clark became more outspoken about his radical views, expressing them openly to his family members who were in the area following Edward Clark’s death,” an FBI agent wrote in an affidavit. “During these conversations, Jeffrey Clark defended Robert Bowers’ killings at the Tree-of-Life Synagogue. Jeffrey Clark also stated that he and Edward Clark had both fantasized about killing ‘Jews and blacks.'”

The relatives also believed 23-year-old Edward Clark may have been planning to carry out an “act of violence” that day before he went to Theodore Roosevelt Island in the nation’s capital and killed himself, the agent wrote. “According to (two relatives), Jeffrey and Edward Clark believed that there would be a race revolution, and they wanted to expedite it,” the affidavit says.

Jeffrey Clark has remained detained in federal custody since his arrest. He had pleaded not guilty in November to illegally possessing firearms and high-capacity magazines for rifle ammunition.

Public defender David Bos has said there’s no connection between his client and Bowers. After Clark’s arrest, Pittsburgh-based U.S. Attorney Scott Brady’s office issued a statement saying there is no evidence that any other individuals besides Bowers “were involved in, or had prior knowledge of” the deadly attack on the Tree of Life Synagogue.

Bos has said his client’s “distasteful comments” on the internet are constitutionally protected free speech and don’t make him dangerous.

Clark told FBI agents that he was a member of white nationalist groups “and followed their ideology,” a court filing says. He also said he and his brother became interested in guns after the 2016 presidential election “because they believed there was going to be a civil war,” the filing adds.

Jeffrey Clark’s Gab username was “DC Bowl Gang,” an apparent reference to the haircut style of Dylann Roof, the white supremacist who shot and killed nine black people in 2015 at a church in Charleston, South Carolina.

The brothers attended the “Unite the Right” white nationalist rally in Charlottesville, Virginia, that erupted in violence in August 2017. Their relatives believe the brothers were photographed in Charlottesville standing next to James Alex Fields Jr., who plowed his car into a crowd of counterprotesters, killing 32-year-old Heather Heyer.

Clark’s relatives told the FBI he abused drugs. They said he and his brother often stayed home to smoke marijuana and play video games such as “Ethnic Cleansing,” according to the FBI.

Clark told FBI agents he had contact with Bowers on Gab but became “evasive” when asked about those conversations, a court filing says. Clark also was reluctant to talk about his brother but told agents he believed his suicide had nothing to do with Bowers, the filing adds.

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