A dispute over a $25 service charge led to a shootout at a Mississippi gun store that left a father and son dead and another father and son injured, according to news reports.

Jason A. McLemore, 44, and his son, Jacob Edward McLemore, 17, were killed in the shooting on Saturday at McLemore Gun Shop, located near Picayune, Miss., according to the Sun Herald. The elder McLemore was the owner of the shop.

Audy McCool, 52, and his son Michael McCool, 29, were both seriously wounded, the Sun Herald reports. Audy McCool was in stable condition in the intensive care unit of a hospital, but no condition was available for his son.

Pearl River County Chief Deputy Shane Tucker tells WDSU.com the McCools entered the gun shop at about 3:15 p.m. Saturday to pick up a gun that had been dropped off for repair.

The two men got into an argument with Jason McLemore's wife, a co-owner of the store who was working as a clerk, about a $25 service fee because the gun had not been repaired. WDSU.com reports she sent a text to her husband asking for help.

When Jason and Jacob McLemore arrived, the situation quickly escalated and shots were fired, Tucker said.

McLemore's wife, who also is Jacob's mother, took shelter behind the counter and called 911. She was not injured.

It's unknown who started firing first, investigators tell the Associated Press. No charges have been filed.

"It's still under investigation. There will be lots of work to sift through the evidence collected and statements and see where that steers the investigation," Tucker tells the Sun Herald. "That will be done in the following weeks and months."