A mixed-martial arts fighter was one of two Americans gunned down in their car before dawn Monday as they waited to cross the border from Tijuana to the U.S. Witnesses reported seeing a gunman approach and fire into the men’s pickup truck. The two men were age 25 and 28, the Baja California’s Attorney General’s Office said, and were later identified as Salcido Luna and Kevin Joel Romero. The San Diego Union-Tribune reported both men lived in Tijuana, but worked in San Diego for West Coast Beverage Maintenance. Luna was a professional fighter. Investigators said they found 9-mm shell casings at the scene, an ammunition popular with Mexican drug cartels, according to the AP.