Deputies said that four men were walking out of the store with diapers and began loading them into an SUV when they were approached by a Walmart loss prevention employee.
The incident unfolded at the Clarcona Ocoee Road store in Pine Hills about 8 a.m. when three people tried stealing diapers and other items, Sheriff's Office Capt. Angelo Nieves said.
The 19-year-old, who was hit multiple times, shooting victim was not immediately identified.
"I see them surrounding the auto (and) the boys throwing stuff in", she said.
Kirmani said she was too busy taking cover to see the shooting take place. "I heard shots and then we just ducked down, because we didn't know where the shots were going".
Deputies say they were called to a South Florida Walmart after a shopper shot and killed a suspected diaper thief in the parking lot.
Nieves' news release said, "While helping the employee, the customer felt threatened by one of the suspects, who the customer believed was arming himself".
Deputies say the auto used in the crime was stolen in a carjacking January 14.
That's when the armed customer intervened, firing his weapon, and hitting two vehicles in the parking lot, causing one to spin off.
The suspects took off in their vehicle before crashing it into two other cars in the parking lot.
The suspect later died at a hospital after deputies found him at a gas station. The one who was shot made it as far as a gas station across the street.
The customer who fired his gun is cooperating with the investigation, the Sheriff's Office said.
Nieves said the four suspects got into the maroon Nissan Rogue and fled the scene.
Workers at the Citgo told Channel 9 the injured suspect walked in and fell to the floor. Deputies didn't say whether he'll face charges.