A Pennsylvania man arguing with his girlfriend outside a 7-Eleven convenience store while allegedly wielding a screwdriver shot and killed a woman who tried to intervene with a gun — taking it away from her and opening fire, cops say.

Surveillance video obtained by The Philadelphia Inquirer and local ABC affiliate WPVI shows John Kelly, 45, allegedly gunning down Lauren Jardine with her own firearm, which she was illegally carrying, during a fight over the weapon, according to prosecutors.

Philadelphia Assistant District Attorney Jeff Hojnowski told local media outlets that Jardine, 33, was simply walking by when she saw Kelly holding a screwdriver and arguing with his girlfriend outside a 7-Eleven at 12th and Chestnut Streets in Center City on Friday at around 5:45 p.m.

Jardine intervened and a verbal altercation ensued, with Jardine allegedly drawing her illegal pistol on Kelly — sparking a struggle between them over the firearm, cops say in a probable cause affidavit obtained by The Inquirer. Kelly, who is charged with murder, allegedly wrestled the gun away from Jardine and fired at her multiple times, including two shots while hovering over her after hitting Jardine in the head, cops say.

“At some point, he is able to disarm her from the firearm,” Hojnowski told reporters, according to KYW Newsradio. “He gets up, and he is kind of standing up to her right-hand side, as she is attempting to get up, you hear another shot. You don”t see a muzzle flash or anything, but you hear another shot, and she falls to the ground.”

One of the shots allegedly came as Jardine was trying to grab and hold onto Kelly’s screwdriver, with Kelly telling her, “put it down,” before pulling the trigger, according to the affidavit. He then allegedly placed the gun in a mailbox.

“She was helping someone,” Jardine’s mother, Ada Jardine, told The Inquirer. “She was probably trying to tell him to leave her alone,” she said, in reference to Kelly’s girlfriend.

Jardine was reportedly in Center City for a job fair, with detectives finding her bag filled with job applications. Ada Jardine said she was trying to get a commercial driver’s license and certificates to operate forklifts and repair HVACs.

Arrest records show that Kelly has had several run-ins with law enforcement in the past, including charges in April for criminal trespass, making terroristic threats, and harassment. A manager at a 7-Eleven near 12th and Filbert Streets has reported Kelly to police multiple times and accused him of harassing employees and customers, along with theft.

“I know where you live,” Kelly told the manager after one incident, according to police. “I know what station you take the train from,” he allegedly said.

Kelly pleaded guilty to the charges in May and was sentenced to nine months of probation as a result, The Inquirer reports. Court records show that he is due in court on Sept. 22 for a preliminary hearing in his most recent case.