A thief was killed in firing by a security guard of the Hindustan Paper Corporation’s mill at Panchgram when he and his four accomplices attacked the security personnel posted there, sources said on Monday. The gang of five thieves armed with weapons had entered the defunct paper mill at around 3.45 p.m. on Sunday and tried to steal the equipment lying there, the sources said. They were spotted by three private security guards on duty when the thieves were about to flee. The thieves attacked the security guards, one of whom fired in self-defence. A bullet hit one of the thieves and the rest of the gang fled. The injured was rushed to Silchar Medical College and Hospital where he was declared brought dead, the sources said. District Superintendent of Police Pabindra Kumar Nath, who had rushed to the spot, said the body is yet to be identified and investigation into the incident is on. Police have seized the 12 bore double barrel gun of the security guard, he added. Cases of theft at the defunct paper mill have been on the rise and the last one was reported about a month ago, the sources said.