ATLANTA (AP) — A man who complained there was too much mayonnaise on his sandwich opened fire at an Atlanta sandwich shop, killing one employee and injuring another, police said.

The shooting happened around 6:30 p.m. Sunday at a Subway restaurant attached to a gas station in downtown Atlanta. Police said the man argued with the two female workers before shooting them.

“This was a very tragic situation that did not have to occur," Atlanta police Deputy Chief Charles Hampton Jr. told reporters Monday.

He said a 36-year-old man believed to be the shooter was arrested Sunday evening after someone whom police are not identifying provided them with information. Hampton said police are not immediately releasing the suspected shooter's name because of the ongoing investigation.

The woman who died was 26 years old. The other woman, 24, remained in critical condition Monday, Hampton said. The injured woman's 5-year-old son was in the restaurant at the time, and Hampton lamented the trauma that that child will have to deal with.

“It’s frustrating that we have a 26-year-old female who is no longer with us," Hampton said. "It frustrates me that we had an individual with a firearm who decided that was the answer to resolve a conflict over a sandwich.”

“It just breaks my heart to know that someone has the audacity to point a weapon and shoot someone for as little as too much mayonnaise on a sandwich,” restaurant co-owner Willie Glenn told WSB-TV.