Tourists, members of Congress, furloughed federal employees, office workers on their lunch breaks — plenty of people witnessed it.

B.J. Campbell and his wife, visiting from Oregon, saw it begin.

Near the White House, a black Infiniti with a woman behind the wheel sped past a security checkpoint at 15th Street and Pennsylvania Avenue NW.

An instant later, blocked from going any farther by a concrete barrier, the woman quickly turned the car around, Campbell said. “The Secret Service guy was just having a cow, yelling at her and banging on the car.”

Officers raised a metal barrier, trying to stop her, he said. “She gunned it. She ran the barricade down,” Campbell said. “And the guy — it knocked him up onto her hood.

Police had a confrontation with a woman in a black car and engaged in a brief car chase with her before shots were fired outside the U.S. Capitol on Thursday. (Thomas LeGro/The Washington Post)

“He rolled off into the street.”

“It looked like they were scared or lost,” Shawn Joseph, a passerby who lives in the District, said of the driver he saw near the White House, ramming the barricade put up by uniformed Secret Service officers. “Whoa!” the officers yelled. “Whoa!”

Olivia Huckaby was on her lunch break when she heard an officer on a loudspeaker ordering: “Run to the park! Move away from the White House!” With dozens of other people, she ran to Lafayette Square. “It was so frightening. With the Navy Yard shooting just happening, we didn’t know what to think.”

As she watched, the car sped east on Pennsylvania Avenue, police cars in pursuit.

A little over a mile away, the Infiniti stopped and briefly rammed a series of police vehicles on the west side of the Capitol, where British tourists Kathryn and Damian Smith happened to be standing, admiring the building’s architecture.

When the commotion started, “they made us run toward the Capitol,” Kathryn Smith said. The couple saw the black car bang into a metal barrier, then into a police car or two.

Regina Romero, visiting from Sacramento, was there, too, near the James A. Garfield Monument and the Capitol reflecting pool, as officers stepped slowly toward the Infiniti with guns drawn. But the driver maneuvered the car free.

As Romero looked on, the Infiniti sped north toward Constitution Avenue.

* * *

At Constitution and First Street NW, Giancarlo Reflo, a tourist from Malta, was sitting on a bench. As the Infiniti came toward him, chased by a swarm of police cars, Reflo looked up from the map he was reading. “At first, I thought the driver was trying to get out of the way of police,” he said. Then he realized otherwise.

The fleeing car zoomed past him, turned right on Pennsylvania and crashed a few blocks away, in front of the Hart Senate Office Building at Second Street and Maryland Avenue NE. There was “lots of screaming and shouting,” Reflo said.

“By that time, I was hiding in the bushes, because I was so scared.”

Dave Caldwell, an intern for a gay rights group, was in line at a security checkpoint in the Hart Building when a guard yelled: “Everyone outside! Everyone outside!”

Making his way to the exit, he heard “three really loud pops, like right outside the door.” He stopped and turned as the guard began shouting again.

“Everyone inside! Everyone inside!”

Caldwell ducked into the office of Sen. Pat Roberts (R-Kan.) and holed up there, worried that a gunman was headed for the building. “I was about to, like, hide under a desk. . . . With the government shut down and things of this nature, I just thought there was such high tension that somebody was really mad at the government.”

About 25 people waited anxiously in the office for nearly an hour. At one point, he said, the senator tried to remove a ceremonial military sword from its wall mount.

Caldwell said the incident was “probably the scariest thing that’s ever happened to me.”

* * *

“It was almost like two very rapid bursts, very loud,” said Rep. Gerald E. Connolly (D-Va.), who was standing on a balcony at the Capitol.

“That’s when we saw people fleeing, and we realized this was no fireworks,” he said. Before someone hurried onto the balcony and ushered him back into the building, he saw police officers swarming the Capitol grounds below him.

“It sounded like the first volley of a 21-gun salute,” Connolly said.

“Eight bangs, real fast, in a row,” said Matt McKeighan, an intern who lives at Third Street and Maryland Avenue NE. His neighbor Justin Herman, a furloughed federal worker, said, “I heard, ‘Boom, boom, boom, boom.’

“It sounded like a clip unloading.”

Or, “like an explosion,” as Ro­mero, the tourist from Sacramento, put it. She said she heard about 10 loud bangs, which turned out to be lethal gunfire.

* * *

In a building about a block from the shooting scene, Berin Szoka, president of the nonprofit group TechFreedom, heard what he thought was a car backfiring. But instantly, he heard another loud pop, then another and another.

“Then I heard the rest, and I hit the floor.”

Minutes passed. When he dared to get up and peer out a window, he saw officers rushing about on the streets, carrying assault rifles and wearing body armor and helmets. With police radio chatter crackling through loudspeakers, Szoka heard that a suspect had been shot in the head and wasn’t breathing.

She was 34 years old, from Stamford, Conn., authorities said. Why she tried to breach security at the White House and led police on a chase wasn’t immediately clear.

“The scene here is surreal to start with, because Capitol Hill is totally dead because of the shutdown,” he said. “All of a sudden, this happens.”

From the window, he saw one officer hurrying from the black Infiniti.

He was carrying something.

* * *

David Loewenberg, an intern furloughed by the Education Department, also saw the officer with a bundle in his arms.

Hearing the shots, he had ran out of his basement apartment and hustled to Second and Constitution nearby.

“Police were swarming at that location,” said Loewenberg, who heard eight or nine shots.

It turned out that the woman wasn’t alone in car. With her was a year-old girl.

That was what Szoka and Loewen­berg saw when the smoke cleared.

“A police officer hugging a small child,” Loewenberg said, “taking her away.”

David Nakamura, Ben Pershing, Ed O’Keefe, Rosalind S. Helderman, Susan Svrluga, Paul Kane, Petula Dvorak, Peter Hermann, Justin Jouvenal and Matea Gold contributed to this report.

Clarification: earlier versions of this story misspelled the name of the town in Connecticut where the driver of the black Infiniti reportedly lived.