Heated arguments that followed an alleged insubordination led to a naik shooting dead his senior, a havildar major, at the army shooting range at Haripur village in Adampur near here afternoon. Sources said Malkit Singh, 38, who hails from Dera Bassi in SAS Nagar district, pumped two bullets from his rifle into the chest of havildar major Rajiv Kamal, 39, killing him on the spot. Kamal, who hails from Bihar, and Malkit were part of the 55 Mechanised Brigade stationed at Beas in Amritsar district and were taking part in the routine practice. Malkit was later arrested by the Jalandhar (rural) police, who also recorded the statements of the soldiers who were witness to the incident. According to the police, the two were not on good terms for quite some time. They said that on Tuesday when Kamal was practising shooting at the range, he asked Malkit to stand behind for help, but the latter refused saying it was against his job profile and asked the former to depute a jawan instead. This led to an exchange of words between the two following which Malkit took out his rifle and fired two shots at Kamal.