A Dallas mother was forced to defend her son when a meetup in a Kroger parking lot went south Monday, police said.

The 16-year-old had arranged to meet with three men outside the grocery store on Ga. 278 to buy a cellphone he saw advertised on Snapchat, according to Dallas police. He brought his mother along, and she brought her firearm.

The mother fired a single shot when the men attempted to rob the boy, Assistant Chief Bill Gorman said. It scared the alleged attackers away.

“It sounds like this particular mom and son did everything appropriately,” Gorman said. “They met at a very well-traveled public spot in the afternoon, and of course she has the right to carry a firearm anywhere in this state.”

Officers were called to the Kroger to investigate about 1:45 p.m. They found the teenager with a bloody nose.

He told the investigators he met the men by the pumps at the fuel center. They produced a cellphone, but it wasn’t the same one advertised, Gorman said.

The boy followed the men back to their green sedan, where they showed him various other phones, he said. None was the one he agreed to buy.

“At that point in time the three of them attacked him and started trying to get the money out of his pocket,” Gorman said.

His mother watched as the boy was punched in the face and put in a headlock, she told investigators.

“Unbeknownst to the men he was meeting with, his mother was with him in the truck,” Gorman said. “When she saw what was going on, she got out and fired a single shot. The three men got back into their vehicle and fled.”

Gorman said no one was reported injured, and there was no visible damage to any of the surrounding vehicles or businesses in the busy parking lot. It is unknown if the woman’s shot hit the suspects’ sedan.

Investigators are trying to obtain surveillance footage to determine the make and model of the vehicle. They are also working to track down the suspects using evidence from the teenager’s cellphone, Gorman said.

The assistant chief said his department has investigated similar cases of theft during online transaction meetups. The fraudsters are typically trying to sell cellphones or expensive shoes, he said.

Police would typically advise potential buyers to meet sellers in a well-lit public place, and to never go alone.

“They did everything right, and it still nearly went south for them,” he said of the mother and son. “You just have to be aware of your surroundings.”

The mother is not expected face charges, according to Gorman.