A man was shot by police and taken into custody March 28 at the U.S. Capitol Visitor Center. (Photo by Ricky Carioti/The Washington Post) (Ricky Carioti/The Washington Post)

Children touring Washington cowered along walls, one covering his ears, as police used hand signals to direct them to safety after a man wielded a weapon Monday inside the Capitol Visitor Center.

The account of a tense standoff lasting 10 to 15 seconds was laid out in federal court records Thursday that charged Larry Russell Dawson, 66, of Antioch, Tenn., with pointing a spring-loaded BB gun at officers at a security checkpoint before a U.S. Capitol Police officer shot him twice.

Dawson faces a federal charge of assaulting, resisting or impeding certain officers or employees with a dangerous weapon as well as a federal charge of assaulting a federal law enforcement officer with a dangerous weapon after an incident that led to brief lockdowns at the White House and across the U.S. Capitol complex.

Dawson remains hospitalized in critical condition with what police described as gunshot wounds to the chest and thigh. Police had initially said he would be charged in D.C. Superior Court with assault with a deadly weapon and assault on a police officer while armed.

In arrest and search warrant affidavits, U.S. Capitol Police Special Agent Kathryn Rivera said surveillance video and witnesses described the anxious moments beginning at 2:37 p.m. after a metal detector sounded as Dawson passed through and then allegedly pulled out what appeared to be a semiautomatic handgun and pointed it at officers Quincy Brisco and Jerry Smith.

This 2004 combo photo provided by the Williamson County Sheriff's Office in Franklin, Tenn., shows Larry R. Dawson. (AP)

Backing away, Brisco drew his handgun and turned it on Dawson, and Smith also drew his weapon, Rivera said. Dawson ignored orders to drop his weapon, Rivera said.

“Civilians, including children, crouched against thc CVC’s walls and behind the metal-detector equipment to avoid gunfire,” Rivera wrote. Officers “with weapons drawn, used hand signals to usher a boy, with his hands over his ears,” to safety, and a woman “grabbed a child by the hand and raced with the child to crouch behind officers.” Smith eventually shot Dawson twice, Rivera wrote.

Dawson will appear in U.S. District Court when he is released from the hospital and is likely to face detention.

The two counts carry a statutory maximum of 25 years and 30 years in prison, respectively, according to an announcement by U.S. Attorney Channing D. Phillips of the District and U.S. Capitol Police Chief Matthew R. Verderosa.

Police said they held in storage a silver 2015 Dodge Ram 1500 truck, believed to be Dawson’s, and obtained a warrant to seek such evidence as firearms, BB guns, imitation firearms, receipts or paperwork for weapons or ammunition; vehicle ownership records; and possible mission statements or plans, Rivera wrote. Court records did not disclose what was found in the truck.

Dawson was familiar to Capitol Police for three protests or security issues in 2015, the affidavit states. On June 1, police barred Dawson from entering House office buildings when he tried to bring in a prohibited sign. He was stopped again June 2 for an unspecified breach of security. And Dawson was arrested Oct. 22 for disrupting lawmakers by shouting Bible verses from the House gallery and running from an officer escorting him out.

The U.S. Capitol visitors center reopened Tuesday. (Jonathan Newton / The Washington Post) (Jonathan Newton/The Washington Post)

Dawson was freed pending his next hearing in the alleged disruption. Dawson wrote a D.C. Superior Court judge in December, saying he would not return to court, writing, “No longer will I let myself be governed by flesh and blood, but only by the Divine Love of God!!!!”

Rivera, in her affidavit, said that in interviews with Capitol Police, Dawson “expressed his interest in meeting with then-Speaker of the House John Boehner [R-Ohio] regarding raising the minimum wage and asserted that God had communicated with him in prayer and scripture to get him to demonstrate on minimum wage.”

Besides Dawson, a female bystander sustained what police called a minor injury, Verderosa told reporters Monday. An update on her condition was not immediately available from police Thursday afternoon.

Lawmakers were mostly away for their spring recess Monday, but the incident jangled nerves after terrorist attacks in Brussels and Paris.

Police raised barricades and shut down pedestrian and vehicular traffic outside the Capitol and congressional office buildings for about an hour, and the U.S. Secret Service halted movements around the White House for a few minutes.