A person of interest who was captured on surveillance video is being sought in the shooting, Hobart police said.
The shooting occurred at about 7:30 p.m. Sunday at the Walmart at 2936 E. 79th Ave. in a busy commercial district along U.S. Route 30.
RELATED: 2 shot at Walmart in Hobart; person of interest sought
Prior to the shooting, two men who knew each other were fighting inside the store.
The man and his 9-year-old son were shot while leaving the store. In response, a man with the victim started shooting at the gunman, police said.
Worker Darrell Grigsby was outside when gunfire rang out.
"Everybody hit the ground. That's when a lady said that a little boy got shot. It was like a war. They were shooting at each other," Grigsby said.
A Walmart associate said employees had recently undergone active shooter training and told patrons to take shelter when they heard the shots.
"It was a mad house. Everyone was yelling into a back room," another shopper said. "My youngest almost got run over. I was yelling, 'Watch out for the kids!'"
Another patron recognized herself and a friend in the surveillance photo distributed by investigators. They were standing just feet from the "person of interest" in the photo.
"If he would have turned around right there I would have been shot," said Diana Johnson.
The shooting is being investigated as gang related, and the FBI violent gang task force will be adopting the investigation, Hobart police said.
The same 25-year-old Gary man was also shot several times six weeks earlier in Gary.
As of late Monday afternoon, Hobart police had no one in custody.