HOUSTON --Detectives are searching for two men who shot and killed a 22-year-old during an argument at a bar in northwest Houston last month. Detectives say Luis Arturo Martinez, a security guard, was tending to an argument between two groups during the early morning hours of January 31 at a bar in the 8300 block of North Houston Rosslyn, according to a Crime Stoppers statement. Martinez went to see what was going on, and at some point, shots were fired. He was struck by a bullet and died at the scene. Detectives say the two suspects were described only as Hispanic males. The shooter is in his 20s, about 6 feet tall, 250 pounds with a distinctive large scar on his inner left forearm. The other suspect is in his 20s, about 5 feet 9 inches tall with a thin build. Anyone with information regarding their identities is asked to contact Crime Stoppers at 713-222-8477.