Howard Prager, 66, and his klezmer band were set up Monday morning in chairs on a slow-moving flatbed truck as they pulled into the lineup for Highland Park’s Fourth of July parade. 

There hadn’t been a parade for three years, since before the pandemic. “People were so happy to be out,” he told USA TODAY. 

Maxwell Street Klezmer Band launched into an upbeat tune, a song made for weddings and celebrations. That’s when they started seeing people running. 

At first, Prager thought there must be a celebrity or something in the parade they were running to see. 

“Then I saw panic on their faces,” he said. “We saw moms and dads with strollers. We saw adults. We saw young people. And they’re all coming toward us.”

Six people were killed and dozens more were injured Monday after a gunman opened fire on the parade around 10 a.m. in Highland Park, a suburb north of Chicago. Residents were warned to shelter in place throughout the day as a search unfolded. Authorities said a person of interest was taken into custody Monday evening.  

‘I grabbed my kid and ran’:6 dead, dozens injured in shooting at July 4th parade in Chicago suburb

The shooting turned the family-friendly event into a crime scene, with abandoned lawn chairs, wagons and bikes scattered along the parade route. 

Alexander Sandoval, 39, a contractor, shook as he recounted the scene with his 5-year-old son, his partner and her 6-year-old daughter. He had set up chairs in front of the stage at 7 a.m., three hours before the festivities began.

“When everything started happening, we thought it was the Navy saluting the flag,” he told USA TODAY. “Shots rang out. I grabbed my kid and ran.”

The parade, part of a daylong celebration, is a community institution in Highland Park, an affluent Chicago suburb know for its leafy suburban streets.

The Illinois State Library’s digital archives show annual pictures from at least as far back as the mid-1960s, floats towed behind station wagons. In one, the historical society poses. In another, a mobile Iwo Jima statue rolls as an honor guard stands at attention.