SEATTLE — Federal prosecutors vow to keep investigating the neo-Nazi hate group Atomwaffen.

“This is a starting line, not a finishing line,” Brian T. Moran, U.S. Attorney for the Western District of Washington said Wednesday after the arrest of four alleged members of the group earlier that morning. “This is the start line, the charges may change, evolve over time as we analyze evidence.” 

Mary Fan, a former federal prosecutor in southern California who’s now a professor of law at the University of Washington, hypothesized about where the investigation could go. 

“It's wise hedging, where normally you have organizational crimes like this, where you have multiple actors, where some are charged and some are not yet identified, you're going to want to build your case,” Fan said.

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The four arrested on Wednesday were charged with conspiracy to mail threatening communications and commit cyberstalking after mailing and posting threatening messages to journalists, including KING 5 Investigator Chris Ingalls, who for months had been investigating the group. Members of the Anti-Defamation League also received threatening messages, which included home addresses and other personal information to show the victims that they knew where they lived.

The crime carries a maximum five-year sentence, although Fan doubted a full sentence would be imposed. But the arrests give prosecutors leverage.

“Depending on what's charged or not charged, there are major incentives to cooperate,” Fan said.

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Fan prosecuted cartels and drug organizations, not hate groups, but she says all organizations have things in common and vulnerabilities.  

“Prosecutors, especially federal prosecutors, have a lot of experience in processing organization-type crimes,” she said. “So what you're thinking about is perhaps uncovering more of the conspiracy, more of the co-conspirators and more planned acts that haven't yet surfaced.”