Spencer Stone, one of the three U.S. citizens who were celebrated as heroes after thwarting a terror attack on a French train this summer, was stabbed in Sacramento, California.

The BBC reports that an Air Force official informed the news organization that Stone was attacked while defending a friend and is currently in stable condition at a local hospital.

Stone was stabbed repeatedly early Thursday morning outside of a bar at 21st and K Streets, reportedly suffering a wound to the heart and to his left lung. The Sacramento Police Department confirms that an assault occurred at that location just before 1 a.m. The police have not, however, said who was injured or named a suspect.

According to the authorities, the incident is “not related to a terrorist act,” and alcohol may have been a factor.

CBS reports that a statement released by the U.S. Air Force reads, “A1C Spencer Stone has been transported to a local hospital, and is currently being treated for injury. The incident is currently under investigation by local law enforcement. He is currently in stable condition.”

The owner of a liquor store in the area claims to have a video of the incident which appears to show five to six men attacking someone at an intersection.

In August, Stone, along with Anthony Sadler and Alek Skarlatos, were on a high-speed train bound for Paris when they heard what sounded like gunfire. Once the three vacationing Americans saw the gunman, who was struggling with another passenger, they sprung into action to subdue the potential terrorist.

As quoted in the Washington Post, Stone described the swift action that came into play before the gunman, saying, “He seemed like he was ready to fight to the end. So were we.”