On March 22, an argument broke out at Falah Barber Shop in West Philadelphia. An angry, unidentified 40-year-old man pulled out a gun and began to open fire at customers and employees, who were huddled together in a crowded room, in what appeared to be an indiscriminate manner.

Teenager Yusaf Mack, who was present at the time of the incident, described what he saw moments before the shooting in comments to NBC Philadelphia, “[The soon-to-be gunman and another individual] were arguing… They were taking it too far and one of the barbers said, ‘chill out.'” At that moment, the enraged customer produced his weapon and unleashed round after round on customers and employees of the barbershop. Children were present in the building at the time of his assault. Witnesses and investigators have yet to determine if the shooter had a specific target as the room in which he was firing was crowded and full of people.

Meanwhile, an armed concealed carry permit holder, who happened to be standing outside, charged into the building and took down the shooter with a single shot to the chest before fleeing. Eyewitness Yusaf Mack said, “He just shot him and when he was done shooting he ran.” The rampaging gunman was later pronounced dead at Presbyterian Hospital. The concealed carrier who shot the gunman surrendered himself to police later that day.

Police say that the gunman was the only individual injured in the shootout, as the concealed carry permit holder intervened before any of the gunman’s bullets could meet their marks. Philadelphia police are treating the fatal shooting of the gunman by the heroic bystander as an act of self-defense and, pending an investigation, are unlikely to press charges.

Philadelphia Police Captain Frank Llewellyn told NBC Philadelphia, “The person who responded was a legal gun permit carrier… He responded and I guess he saved a lot of people in there.” CBS Philly quoted Captain Llewellyn as saying, “There were numerous people in there, so it could have been a lot worse.”