IOWA CITY, IOWA -- A right-wing conspiracy theorist from Iowa was among the first to break into the U.S. Capitol during last week's deadly pro-Trump insurrection, chasing and menacing a Black police officer, federal agents said Tuesday.

Douglas A. Jensen, 41, surrendered to police in his hometown of Des Moines on Friday, two days after the Jan. 6 rampage in Washington, D.C., left five people dead and disrupted U.S. democracy.

Investigators say he told them he positioned himself to be among the leaders of the Capitol siege because he was wearing a shirt promoting QAnon, the apocalyptic conspiracy theory that he follows.

"He wanted to have his T-shirt seen on video so that `Q' could `get the credit,"' FBI special agent Julie Williams wrote in a statement outlining the allegations against Jensen, who posted photos of himself at the riot on social media.

Jensen made his initial federal court appearance via video from jail in Des Moines on Tuesday.

A grand jury indicted him on six counts, including obstructing law enforcement during a civil disorder, resisting Capitol Police officer Eugene Goodman, violently entering and remaining in a restricted building, and disorderly conduct.

The FBI's statement cited video footage showing Jensen leading a crowd of people toward Goodman, who was by himself and armed only with a baton.

Jensen ignored Goodman's orders to stop and put his hands up and led the crowd toward the officer in a menacing manner, the court filing said. Goodman was forced to retreat up a flight of stairs toward the Senate chamber to seek backup.

"The video footage captures Jensen chasing the officer up the stairs and shouting at the officer," Williams wrote. "Twice more, the officer orders Jensen to stop and raises his hand to keep Jensen from advancing. Both times Jensen continued to advance in a menacing manner, with the crowd following behind him, forcing the officer to continue to retreat."

Ultimately, Goodman got to an area occupied by several additional officers, who were able to stop the rioters from advancing. Many have praised Goodman for keeping the attackers from getting inside the Senate chamber while members were still present.

At the time, senators had been debating an effort backed by some Republicans to refuse to certify Joe Biden's presidential election victory in key swing states. The attack left a police officer dead and delayed congressional action for hours. Jensen is among dozens of people facing charges.

Jensen's brother, William Routh, 54, of Clarksville, Arkansas, told The Associated Press on Saturday that the two had been communicating about QAnon for months.

"I did not believe in QAnon and I told him to be careful what he listens to because no one knows what QAnon is. Nobody knows who is Q, but I don't know where he is getting his information," Routh said.

Jensen believed Q was either Trump or someone close to Trump, and that "he was told by Q to be at that spot at that time," Routh said, referring to the events at the Capitol.

In May 2019, an FBI bulletin mentioning QAnon warned that conspiracy theory-driven extremists have become a domestic terrorism threat and were "very likely" to commit violent crimes inspired by their fringe beliefs.

Jensen is being held at the county jail in Des Moines pending his potential transfer to face charges in Washington, D.C. A judge scheduled a detention hearing for next week.

Jensen's employer, an Iowa-based masonry contracting company, fired him on Friday.

AP reporter Heather Hollingsworth contributed to this report from Mission, Kansas.