Jason Van Tatenhove was once the national media director of the Oath Keepers, a job he was hired for in 2014.
Van Tatenhove testified to the Jan. 6 House committee about the group’s radicalization and how Stewart Rhodes, the group's founder, used conspiracy theories to increase membership and funding.
Van Tatenhove even lived with the Rhodes for several months, but has not been actively involved with the group since about 2017.
He told the committee on Tuesday that he noticed the group getting more radical over time, drifting "further and further right — into the alt-right world, into White nationalists and even straight-up racists and it came to a point where I could no longer continue to work for them."
He said he finally decided to leave the group was when he heard members talking about how the Holocaust was not real.
"That was for me something I could not abide," he said.
More recently he has spoken out about the danger posed by violent extremist groups like the Oath Keepers, his lawyer said.
In an interview with the Denver Post last year, Van Tatenhove described himself as a propagandist for the Oath Keepers. For a year and a half between 2015 and 2016, he posted blogs for the organization, ran the social media networks and appeared in videos.
The former owner of a tattoo shop in Fort Collins, Colorado, said that during that time the group turned from a loose network worried about government overreach to a hateful organization.
Van Tatenhove said he imagined himself as his journalism idol, Hunter S. Thompson, who embedded with motorcycle gangs for his first nonfiction book.
“I had these grand intentions that I was going to write my break-out novel, but what wound up happening is I just became a propagandist for them,” he told the Denver Post. “I failed that internal mission pretty fantastically.”