Police in Washington, D.C., on Sunday arrested a North Carolina man after they said he walked into a popular pizza restaurant and began firing an assault rifle. The man, who sent customers and employees fleeing, told police he had come to “self-investigate” an election-related online conspiracy theory involving Hillary Clinton.

No one was injured.

Police arrested Edgar Maddison Welch, 28, of Salisbury, N.C. They said Welch walked into Comet Ping Pong, in the city’s Chevy Chase neighborhood, and pointed the rifle in the direction of an employee, who fled and called police.

Police said Welch then fired the rifle inside the restaurant.

Several neighboring businesses were locked down temporarily, The Washington Post reported. Welch was charged with assault with a dangerous weapon.

The restaurant, as well as its owner and staff, were at the heart of an ominous chain of events centering on fake news stories linked to Clinton.

In the days before the Nov. 8 election, Comet’s owner and employees said they were threatened on social media after fake news stories claimed that Clinton and her campaign chief, John Podesta, ran a child sex ring from the restaurant’s back rooms, which attract diners with ping pong tables.

James Alefantis, Comet’s owner, told The New York Times that he received menacing messages such as “we’re on to you” on his Instagram feed. The messages soon turned to death threats, The Times reported, and Alefantis soon discovered dozens of “made-up articles” about Clinton kidnapping, molesting and trafficking children in the restaurant’s back rooms.

Alefantis, a Clinton supporter, said he had never met her and his 40 employees had unwittingly become “real people caught in the middle of a storm of fake news.”

Alefantis, 42, suspected that a onetime relationship with David Brock, a former right-wing journalist who became an outspoken advocate for Clinton, may have made him a target.

On Sunday afternoon, Gareth Wade, 47, and Doug Clarke, 50, were sitting down for lunch around 3 p.m., when a server said “someone just walked in with a shotgun,” Wade told The Post.

He recalled that the server “said we ought to vacate the building.”

Police said they recovered two additional firearms inside the restaurant and another weapon from Welch’s car.

Other businesses on the block have also reported receiving threatening phone calls tied to the conspiracy.

“One person said he wanted to line us up in front of a firing squad,” Matt Carr, owner of the Little Red Fox market and coffee shop, told The Post. Carr said he and his employees spent more than an hour in lockdown Sunday.

“This was our worst fear, that someone would read all this and come to the block with a gun. And today it happened.”

Follow Greg Toppo on Twitter: @gtoppo