nbc news has learned that january 6 committee investigators are zeroing in events attended by domestic violent extremist groups throughout 2020. half a dozen sources say investigators are trying to determine if the groups coordinated with other militia movements, rally organizers, and government officials in the weeks before that. and whether events like covid lockdown rallies, counter protests to racial justice demonstrations, protests at capital builds were proving grounds, opportunities, to network or encourage each other to cross red lines into future violence. investigators are also working to find out how so many different groups arrived at the same goal of storming the capitol with a white nationalist conspiracy theory serving as at least one unifying factor among them. it comes just as federal law enforcement agencies warn about