The rally by white supremacists protesting the removal of a statue of Confederate Gen. Robert E. Lee left one counter-protester dead and several injured.
Last year's numbers were the second highest since the Anti-Defamation League began tracking such incidents in 2017 and represented increasing levels of coordination and mobilization, the ADL says.
Joseph Moore wore a wire for the FBI under his white robe.
The indictments of members of at least three separate extremist gangs follows similar charges earlier this week against two dozen alleged white supremacists in Texas, Mississippi and Kentucky.
"There should be no question that Ms. Collins Rudolph and the families of those who perished ... suffered an egregious injustice that has yielded untold pain and suffering over the ensuing decades."
As break-ins and fires raged in the first days of protests over the killing of George Floyd, Minneapolis seemed to descend into a security vacuum. So volunteers banded together and stepped up.
This is the second round of suspected members of The Base to be arrested this week. The group is trying to bring about the downfall of the U.S. government, according to law enforcement.
Swatting is harassing a target by drawing extreme law enforcement responses with fake bomb or shooting reports. The government says the suspect bragged about it in a white supremacist chatroom.
Facebook is beginning to enforce a ban on white nationalist content this week. The move comes as Australia, Germany and other countries pass tough laws to curb hate speech.