ATLANTA - A customer shot two Subway workers, leaving one of them dead, after an argument that stemmed from a complaint about his sandwich.

"Believe it or not, it was about too much mayonnaise on his sandwich," Willie Glenn, the owner of the Atlanta sandwich shop, told FOX 5. "He decided to escalate the situation and from there, that's when all hell broke loose."

The shooting happened around 6:30 p.m. Sunday.

One employee, a woman, died at the scene and the other was rushed to a hospital. Glenn said one of the employees' children was inside the store at the time. 

"One of the young ladies who was killed today, her son was in the store. She had a young son that had to witness all of this," he said.

The owner said the manager on duty returned fire at the shooter, but he got away. Police are still trying to locate the gunman. 

The victims have not been publicly identified as of Monday morning.