Mr. Newbold’s worldview is plain from his Facebook account. In a combative video laden with expletives that he posted a week before the riot, he repeated debunked but widely circulated claims about the election, saying that “it is absolutely unbelievable, the mountains of evidence of election fraud and voter fraud and machines and people who voted, dead people who voted.” When commenters challenged him, he responded with expletives and rejoinders like “Yeah keep laughing, you’re going to be laughing when you’re stomped down.”