What happens next? It's sort of like the presidential situation if no crime is prosecuted (for different reasons with president) it's not easy to get rid of him.  Article says this

Following the release of the report, Shea was suspended from the House Republican Caucus — a serious form of discipline.

He was also stripped of his position as the ranking member of the House Environment and Energy Committee and will be removed from two committees.

"He should resign," Washington State House Minority Leader Rep. J.T. Wilcox tweeted.

"He cannot use House Republican staff, he cannot meet with the caucus, his office will be moved," Wilcox added.

But late Thursday, Shea said he will not resign

[....]

Next steps

State Rep. Laurie Jinkins, a Democrat, said the House needed time to review and digest the full report prior to taking further action.

She added: "In its 130-year history, I am unaware of House members ever having received such a comprehensive and disturbing investigatory report about another member."

The gravity of the findings prompted the Chief Clerk's Office to forward the report to the U.S. Attorney's Office and the FBI, Jinkins said.

"We respect Rep. Shea's right to free speech and his personal beliefs, but those ideals are not what this is about," she added. "This is about a state lawmaker who, according to the investigative findings, engaged in an act of domestic terrorism rather than choosing political or legal avenues to change laws and policies he disagrees with."

Shea could be removed from the state House entirely but that would require a two-thirds majority vote of House members, and, the nonprofit news site Crosscut reports, that "has happened only once in the history of Washington's Legislature." [....]

Where were the prosecutors? Why an independent report instead of prosecution? Confusing. If a district elects a criminal that's not prosecuted, what can you do?