Police said the gunman and his 23-year-old victim were leaving the park after attending the Zone 6 Day, which was billed as a community event for families living in East Atlanta and attended by hip-hop superstar 21 Savage.
But as word spread, the crowd quickly grew
“This event was permitted for a couple hundred and it greatly exceeded that," Schierbaum said.
Thousands heard the gunshots.
“We didn’t even make it to the park. It was like a wave. Everybody was just running. You run and then I run. I didn’t even know where we would run,” one woman told Seiden, asking not to be identified.
Many jumped into their vehicles, creating a traffic nightmare.
“We had a number of police resources that were in the area already and started mitigating traffic in park and on foot and in vehicles,” Schierbaum said.
The motive remains unknown, but investigators believe the shooter knew his victim.
Channel 2's Lauren Pozen learned that Santonio Foster has been charged with possession of a firearm by a convicted felon in the shooting.
Seiden said investigators focused attention on a black Ford Mustang Saturday night. Detectives believe the shooter jumped inside the vehicle after he fired shots into the crowd.
Police said several other people received minor injuries while running away from the park.
The bystander who shot the suspect waited for officers and has been fully cooperative with the investigation, police said.
“We are extremely grateful that nobody else was injured in this incident,” said Deputy Chief Todd Hutchinson. “This suspect opened fire at a crowded public park. This could have been so much worse."
A flyer posted on Facebook and Instagram said a back-to-school event called "Peace in the City" was going on at the park when the shooting happened.
Dwight Harvey, who is the father of the event's organizer, was streaming the event live on his Facebook page when the shooting occurred.
In the video, many children and parents are sifting through backpacks stuffed with school supplies under a pavilion at the park when 12 rapid-fire shots ring out.
After consulting with the State Attorney’s office, detectives do not expect to file charges against the bystander since his actions were within the law according to the preliminary investigation, police said.