A Texas woman allegedly pulled a gun on a Five Below shopper and blasted the store patron multiple times in the parking lot, killing her in front of her daughter after the victim got upset that the suspect didn’t say thank you for opening a door for her, cops say.

“The shooter was saying, ‘Come outside. Let’s handle this outside. Let’s fight outside,'” an alleged witness told local Fox affiliate KDFW about the Tuesday shooting incident, which left 41-year-old Cecilia Simpson dead from multiple gunshot wounds in front of her 20-year-old daughter, per police.

“The mom and daughter were just telling her to like go away,” the witness, an ER nurse who tried performing lifesaving measures, alleged about 22-year-old suspect Keona Hampton.

“The mother and daughter tried to get in the car to de-escalate the situation but the lady wasn’t having it,” the witness said, asking to remain anonymous. “They started to fight and that’s when the lady pulled out her gun and shot her.”

An arrest affidavit obtained by KDFW outlines how Simpson and her daughter were exiting a Five Below discount store in the 3500 block of West Wheatland in the southeast Oak Cliff area of Dallas when Hampton began walking in.

Police reportedly say Simpson held a door open for Hampton, who proceeded to waltz inside without thanking her. This allegedly upset Simpson and she confronted Hampton over it, prompting an argument between them, police said.

Simpson and her daughter walked to their car and then drove to a PetSmart in the same shopping center, according to the affidavit. Hampton allegedly followed them and Simpson alerted PetSmart employees to what was happening.

The two women began arguing again and were both asked to leave the store, according to police. Once in the parking lot, Simpson and her daughter tried leaving when Hampton threw a drink bottle at their vehicle.

According to KDFW, cops say Simpson exited the vehicle and attacked Hampton with physical strikes while yelling to leave her alone. That’s when Hampton allegedly took out a handgun and started firing at Simpson, hitting her multiple times.

Surveillance video allegedly shows Hampton driving away after the incident. Authorities said they tracked her down using her license plate information and arrested the woman later that evening following a traffic stop.

Hampton allegedly admitted to police that she argued with Simpson and said she shot her in self-defense while trying to get Simpson away from her, KDFW reports. The alleged witness who spoke to the station said Simpson’s daughter was hysterical.

“The daughter was next to the mom the whole time,” the woman said. “It’s hard, you know, because the screaming of a child for her mother is never easy and it’s never going to leave my head.”

Hampton was booked into the Dallas County Jail. A bond has not been set.