County artists were among the many Americans who turned to Twitter on Thursday morning (Nov. 8) to react to the news of a mass shooting at a country bar in Thousand Oaks, Calif., that killed at least 12 people.

According to multiple media reports, a lone white male gunman burst into Borderline Bar & Grill late Wednesday night (Nov. 7) and began throwing smoke grenades and firing a handgun into the hundreds of people who were there for a college country night. At least 11 patrons have been confirmed dead, along with Ventura County Sgt. Ron Helus, who was one of the first law enforcement officers to respond to the scene. The shooter, 29-year-old Ian David Long, also died at the scene. No motive has been given for the crime.

Helus was a 29-year veteran who intended to retire in a year, according to Ventura County Sheriff Geoff Dean. Dean fought back tears as he recounted Helus' bravery in running toward the danger within three minutes of the first reports of gunfire. Helus entered the Borderline through the first door and was hit multiple times. He died later at a local hospital. "He gave his all, and tonight, as I told his wife, he died a hero," Dean said (quote via NBC News). "He went in to save lives, to save people."

Borderline's website lists John RichCollin RayeMark ChesnuttLee Brice and Tyler Farr among the artists who have performed there over the years, and Rich was one of the country artists who responded to the tragedy on Twitter Thursday morning, revealing that he was postponing a scheduled press run in New York City to focus on the matter. He offered his respects to Helus, as did Charlie Daniels, while artists including Morgan Wallen. LeAnn Rimes and Margo Price also turned to social media to share their reactions to the news.

Country Stars React to the Mass Shooting in California