A man killed two people, including a policeman serving him with an eviction notice, before he was shot dead by officers in a gun battle in the US state of Texas that lasted 30 minutes. Four people were also injured in the shoot-out near Texas A&M University in College Station. Monday's incident came at a time of national concern in America over gun violence after two recent mass shootings. The dead officer was identified as Brazos County Constable Brian Bachmann, said Scott McCollum, assistant chief of the police department in College Station. McCollum said Bachmann, 41, was shot in front of the house, about two blocks from the Texas A&M campus, and was pronounced dead at a hospital. Police identified the gunman as Thomas Caffall, 35, and the bystander killed as Chris Northcliff, 43, of College Station. City spokesman Jay Socol said authorities were still investigating Caffall's background. It was unclear whether Caffall was renting the home or was being evicted for nonpayment of a mortgage, he said. Officials said the wounded included a 55-year-old woman, who had surgery, and College Station police officer Justin Oehlke, who was in a stable condition after being shot in the leg. Officers Brad Smith and Phil Dorsett were injured by what police called gun shrapnel. Smith was treated at a hospital and released and Dorsett was treated at the scene. "We had officers respond to a 'shots fired' call," McCollum said. "Once the officers arrived, they began to trade fire. The officers defended themselves and called in additional officers." College Station police officers shot and killed the gunman, said Jason James, a sergeant with the police department in nearby Bryan, Texas. A Facebook page listed as belonging to Caffall, which had a photo nearly identical to a driver's licence picture released by authorities, included photographs of rifles he said he had acquired, including a Czech vz. 58 assault rifle. The university issued a "code maroon", warning students an "active shooter" was in the area and asking them to stay away. The College Station shooting comes less than four weeks after a man opened fire in a crowded Colorado cinema during a midnight showing of The Dark Knight Rises , killing 12 and wounded 58. On August 5, a gunman killed six people at a Sikh temple in Wisconsin before committing suicide.