The first thing he heard, Hamond said, was what sounded like gunfire coming from the west side of the Capitol. Roughly 10 to 20 seconds later, he said he saw a black car -- which reportedly carried a woman and her child, who had attempted to ram into a barricade near the White House -- "zooming up" Constitution Avenue, with at least three police cars in pursuit.
"I'm absolutely positive that there was some sort of burst or something that sounded like the gunfire before the car showed up," Hamond told TPM.
The last police car in pursuit slammed into a security barrier that was rising up out of the street on Constitution Avenue. TPM previously reported on a heavily damaged vehicle at Constitution and First Street NW, and pictures of it have been circulating on social media.
"The barriers went up, and he hit the barriers going 60 miles per hour," Hamond said.
The area was then overrun with police.
"Cops on bikes, motorcycles," Hamond said. "Within 30 seconds, the whole place was covered in police."