WASHINGTON (CBSNewYork/CBS News/AP) — A man who fired a rifle inside a pizzeria in the nation’s capital while investigating a fake news story about Hillary Clinton running a child sex ring is expected to appear in court Monday afternoon, police said.

As CBS News’ Weijia Jiang reported, SWAT teams moved in on Sunday afternoon after a man opened fire with an assault rival at the Comet Ping Pong pizza restaurant on Connecticut Avenue.

Bartender Lee Elmore told news outlets that people in the restaurant began to panic as an armed man walked to the back of the restaurant.

“One of the hosts runs up and is like, ‘Did you see that guy? You know, he had a big gun,’” Elmore said.

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Comet Ping Pong is in an affluent area of the city. Police said the suspect – identified as Edgar Maddison Welch, 28, of Salisbury, North Carolina – fired several times and hit and damaged walls, the door and a computer. No one was injured.

“The first couple of police officers had their guns drawn, including automatic rifles, and they were standing behind cars and taking aim; listening to; talking to the suspect,” said witness Sathi Soma. “And after a while, the suspect came out.”

According to a police statement, Welch told police he’d come to the restaurant to “self-investigate” a fictitious conspiracy theory known as “Pizzagate” that spread online during and after Clinton’s run for the White House.

The bizarre rumors about the pizza joint began with a leaked email referencing Clinton and pizza parties. It morphed into fake online news stories about a child sex trafficking ring operating out of the restaurant.

According to the documents, Welch told officers that he had “read online that the Comet restaurant was harboring child sex slaves and that he wanted to see for himself if they were there. He stated that he was armed to help rescue them. He surrendered peacefully when he found no evidence that underage children were being harbored in the restaurant.”

An incident report lists a Colt AR-15 rifle, a Colt .38 handgun, a shotgun and a folding knife among the items seized in the case.

The shooting alarmed those from neighboring businesses all the way to the White House about the real-life dangers of fake news on the internet. One of those people posting on the conspiracy theory is the son of President-elect Donald Trump’s proposed national security adviser.

Even Monday, Michael Flynn Jr., who has posted frequently on the Pizzagate theories, continued to push the conspiracy theory. He’s an adviser to his father, Michael Flynn, whom Mr. Trump has selected to serve as national security adviser.

Flynn Jr., who has accompanied his father to presidential transition meetings inside Trump Tower and lists the presidential transition website as part of his Twitter bio, tweeted Sunday night that, “Until #Pizzagate proven to be false, it’ll remain a story.”

On Monday, President-elect Trump’s team had no immediate response to questions about the conspiracy theory or the roll of Michael Flynn Jr. in the transition.

On Monday, White House Spokesman Josh Earnest, asked about the shooting, said, “There’s no denying the corrosive effect that some of these false reports have had on our political debate and that’s concerning in a political context. It’s deeply troubling that some of those false reports could lead to violence.”

The fake news stories alleging that Clinton and her campaign chief, John Podesta, ran a child sex ring out of the restaurant have been denounced by the owner of the popular pizza restaurant.

“We should all condemn the efforts of certain people to spread malicious and utterly false accusations about Comet Ping Pong,” owner James Alefantis said. “Let me state unequivocally: These stories are completely and entirely false, and there is no basis in fact to any of them. What happened today demonstrates that promoting false and reckless conspiracy theories comes with consequences.”

CBS News justice reporter Paula Reid reported that Welch made his initial court appearance at approximately 4:30 p.m. Monday, escorted by two U.S. Marshals. He was restrained at his hands and feet.

According to Reid, court documents filed charged Welch with assault with a dangerous weapon, carrying a pistol without a license, unlawful discharge of a firearm, and carrying a rifle or shotgun outside the home or business.

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