In Seattle on Wednesday, prosecutors unsealed a conspiracy charge against Kaleb James Cole, 24, a leader of Atomwaffen’s chapter in Washington, accusing him of sending threatening mail and cyberstalking. The others charged were Cameron Brandon Shea, 24, of Redmond, Wash., described as a high-level recruiter for the group; Taylor Ashley Parker-Dipeppe, 20, of Spring Hill, Fla.; and Johnny Roman Garza, 20, of Queen Creek, Ariz.

Authorities said the men took part in an operation called Erste Saule, or “first pillar” in German, which Mr. Shea described in an encrypted chat room as an effort to target “journalists houses and media buildings to send a clear message.”

The goal, Mr. Shea said, was to “erode the media/states air of legitimacy by showing people that they have names and addresses, and hopefully embolden others to act.”

Prosecutors said Mr. Cole and Mr. Shea were the primary organizers. When members of Atomwaffen suggested Jewish or black journalists as possible targets, Mr. Shea and Mr. Cole offered praise. Mr. Shea said he wanted his victims to feel “terrorized.” Mr. Cole suggested buying rag dolls and sticking knives through their heads and leaving them at the locations of their targets, according to the charges.

Authorities said Mr. Cole and Mr. Shea created posters that included Nazi symbols, threatening language and masked figures with guns and Molotov cocktails, then printed and delivered or mailed the posters to their targets.

Among the recipients were a broadcast journalist in Seattle who had reported on Atomwaffen and two people associated with the Anti-Defamation League. In Tampa, Fla., the group targeted a journalist but delivered the poster to the wrong address, and in Phoenix, a poster was sent to a magazine journalist, according to the Justice Department.

Chris Ingalls, an investigative reporter with KING-TV in Seattle, said he was among the people targeted. Federal agents contacted him last month to warn him that Atomwaffen members might visit him in person, so he moved his family out of their home, he said.