FBI agents arrested a suspected white supremacist from Texas Wednesday, accusing him of making hoax calls to local law enforcement to summon a police response — a practice known as swatting — in a scheme that targeted former Homeland Security Secretary Kirstjen Nielsen and a prominent news organization.

In a separate case, the FBI arrested a Seattle man and three others, accused of being members of the Atomwaffen white supremacist group and sending threatening posters to recipients in Washington state, Florida, and Arizona. The victims included journalists and staff members of the Anti-Defamation League.

In the swatting case, the Justice Department said John Cameron Denton, 26, and his fellow members of Atomwaffen made more than 100 hoax calls affecting 33 states.

Prosecutors said the investigation of the swatting conspiracy began in January 2019, when a caller, speaking in a muffled voice and sounding out of breath, claimed to have shot and killed his girlfriend, tied up her two children, and was prepared to set off a bomb. He gave the Alexandria, Virginia address of a member of President Trump's cabinet.

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Court documents say the police never responded, however, because the Secret Service immediately realized the call was a hoax. The cabinet member was not identified in court documents, but law enforcement officials said it was Nielsen, who at the time was Homeland Security Secretary.

Denton, who authorities described as a former leader of the Texas chapter of Atomwaffen, was also accused of participating in swatting calls to a church in Alexandria and the New York City office of ProPublica, a non-profit news organization.

The FBI said Denton met with a person in January who he thought was like minded but who turned out to be undercover FBI agent. He discussed his role in making the swatting calls and said he wanted to target journalists who wrote about white supremacists, according to the charges.

A second man, John William Kirby Kelley, who faces similar charges filed last month, worked with Denton to make or inspire dozens of calls, including one to Old Dominion University in Norfolk, Virginia, where Kelley was a student, authorities said.

That call, on Nov. 29, 2018, caused the university to shut down and issue a shelter-in-place alert. Local police painstakingly searched and cleared every building on campus.

Also Wednesday, authorities in Seattle announced the arrest of 24-year-old Kaleb Cole. Court documents said he was outraged by a 2018 Seattle Times story that identified several people said to be members of the Atomwaffen. Investigators said Cole recorded an audio message discussing "nosy reporters" and saying "We must simply approach them with nothing but pure aggression."

Three other followers of the group were accused of sending similar threatening posters to staff members of the Anti-Defamation league in Washington state, to a house thought to be the residence of a Tampa, Florida reporter, and to the editor of a local Jewish publication in Arizona.

Among those arrested was 24-year-old Cameron Shea of Redmond, Washington. The FBI said Shea was a high-level member and recruiter for the Atomwaffen group. Court documents say he mailed a threatening poster to a reporter for KING, the Seattle NBC affiliate, who had done stories about the group.

Cole has long been a subject of interest to police and federal agents. Last September, police took nine guns from his Seattle-area home, acting under an Extreme Risk Protection Order. Authorized by the state's red flag law, it allows authorities to take guns away for up to a year from people deemed to be a risk to themselves or others.