But rather than the summer sound of Washington locusts the Bachs heard gun shots as they snapped the first photo of their 10-month-old daughter, they explained to CBS News Saturday Morning's Dawn Stensland.
"It was like a can of worms," David explained "Everyone scattered."
While David and his brother Dan were pulled to safety by an officer, Karrie grabbed the baby and ran for shelter elsewhere. The family was later reunited.
CBS News Correspondent Sharyl Attkisson reports it's one of the busiest times of the year for Washington, D.C., and the Capitol is one of a top tourist attractions. The House was in session and the building was packed with visitors when the shots rang out.
"We heard a boom, boom, boom, and my husband told me, 'that's a gunshot,'" said Kimberly Anderson. Another eyewitness, Jilian Simon, described how "all of a sudden I just started hearing screaming and then one shot after another. And then the guards kept telling everyone to run and run and run. And I was too scared. We just hid by a window."
"There was this rapid gunfire one right after another," said another man who witnessed the shooting. "This pop. Pop. Pop. In really quickly sucession. I just grabbed my wife and we crawled along the floor into a little cubby hole and just got out of the way. All hell broke loose for a few seconds and the Capitol police took up defensive positions around us, just kind of trapped us in there for a second, and then they just said, 'get out.'"
"It was very frightening because we didn't know where the gunman was or if they had apprehended him and we just hid," a woman said.
Despite the moments of fear and panic, police say there is no continuing danger and the U.S. Capitol buildings will be open as usual Saturday.