Punjab Police today said that a preliminary investigation into the April 12 incident at the Bhatinda Military Station indicated that the gunner who shot dead four jawans in their sleep did so due to "personal enmity." Addressing a press conference here, Senior Superintendent of Police (SSP), Bathinda, Gulneet Khurana said that the Army gunner had on "sustained interrogation" confessed to stealing an INSAS rifle and to killing four of his colleagues.