An armed man attempting to rob a neighborhood store was shot and killed by a customer who had a concealed carry license, Chicago police said Sunday.

A masked man, later identified as 55-year-old Reginald Gildersleeve, walked into the store and currency exchange about 7 p.m. Saturday on the city's southwest side, displayed a handgun and announced a robbery to an employee, police spokesman Anthony Guglielmi said. The gunman next pointed his weapon at another employee and forced her to the back of the store.

The armed customer then fatally shot the man multiple times, according to the Chicago Sun-Times. Gildersleeve was pronounced dead on the scene at 7:10 p.m., according to police and the Cook County medical examiner's office. He had an extensive criminal history, including prior arrests for robbery, the Sun-Times reported. Gildersleeve was set to have an autopsy performed on Sunday, according to the Chicago Tribune.

"We're looking at it as a self-defense issue at this point"

- Anthony Guglielmi, police spokesman

It wasn't immediately clear whether the customer, who has not been identified, will face charges. Guglielmi said the case is under review by local prosecutors, but the preliminary details suggest that the customer was not at fault.

"We're looking at it as a self-defense issue at this point," he said.

Last month, a Michigan woman with a concealed carry license shot at shoplifters fleeing a Detroit-area Home Depot store, flattening a tire of their SUV. No one was hurt, and the suspected shoplifters were arrested several days later. The woman faces up to 90 days in jail after pleading no contest to a charge of reckless discharge of a firearm. Two other shootings in which citizens fired at lawbreakers or potential lawbreakers also happened in September in Michigan.

"It's a slippery slope" when it comes to the question of whether citizens who are licensed to carry guns should intervene in dangerous situations, if at all, Guglielmi said.

"You have situations like this," he said, referring to the foiled Chicago robbery in which no one else was hurt. "And you have situations that end tragically. The department is not going to advocate for what people should or shouldn't do."

The Associated Press contributed to this report.