Seems Plausible; Needs a More Mainstream Source

 From Andy Ngo's account:

One of the men who was part of the siege of the Capitol building is John Earle Sullivan, an extreme BLM activist from Utah. He was arrested & charged in July 2020 over a BLM-antifa riot where drivers in Provo were threatened & one was shot. https://deseret.com/utah/2020/7/10

1/8/21 KSL:

SANDY — A Utah activist who faces criminal charges in connection with a Provo protest he organized in June claims he attended a pro-Trump rally that turned into a violent attack on the U.S. Capitol in order to see “the truth” about the protests for himself and the organization he represents.

“For me, it’s important from the group and the people around me to see that side of things, to see the truth,” John Sullivan said Wednesday night. “I don’t care, like what side you’re on, you should just see it raw.”

Sullivan, who is the founder of Insurgence USA, a social justice group that calls itself anti-fascist and protests police brutality, was detained by Washington police for about an hour and a half Thursday night, a day after he talked to local and national media about what he witnessed Wednesday.

He was handcuffed the entire time, and said police questioned him about being inside the Capitol and witnessing the shooting death of one of the protesters. He was not arrested.

Sullivan said he also intended to “support the Black community” with his attendance, but also feels it was “important to understand” those who were protesting in support of President Donald Trump.

But some of the 40-minute video he posted to his social media sites contradicts his assertion that he and another woman were “only filming” the actions and not participating as he can be heard in the video encouraging people to join them as they push their way through police barricades.

Just after people broke into the building, Sullivan — wearing a gas mask and wielding an iPhone on a stabilizing stick — and a woman who said Wednesday that she was making a documentary on Sullivan, are on the first porch area outside the entrance looking back over the throngs of people around the Capitol. They can be heard encouraging people to climb the wall, saying, “Come on. Let’s go!”