Four more men have been charged for their involvement in a bar brawl outside a Panama City Beach bar which left a 31-year-old airman dead from blunt force trauma after police say he was struck by a trained MMA fighter.

Ross Allen Johnson of Carterville, Ill., has been charged with manslaughter, accused of delivering the fatal blow to the head of Dayvon Larry, an airman stationed at nearby Tyndall Air Force Base.

Wednesday, Panama City police announced the arrest of four others for their involvement in the incident:

• Timothy Lynn Helton, 32, of Salesville, Ark., charged with simple battery
• Toby LeShane Wallace, 30, Carterville, Ill., charged with simple battery
• John Dero Chester II, 23, of Carterville, Ill., charged with disorderly conduct on the premises of an establishment
• Malcolm David Santiago-Ramos, 26, of Panama City, charged with inciting a riot

According to police, witnesses and surveillance footage show Johnson punching Larry behind his left ear, with Larry then falling to the pavement. Witnesses also told police Johnson is an amateur MMA fighter, with three years of “advanced fighter training.”

Police say the investigation remains open and more arrests are possible.