Murree - Security guard of a private security company was killed in firing of a colleague over minor dispute here yesterday.  Rescue sources said that two security guards of a private company performing duty in Murree were in personal grudge and they exchanged hot words over the same dispute. The verbal clash turned violent after which one security guard opened fire at his colleague killing him on the spot and fled the scene. The body was shifted to hospital for postmortem and the police after registering a case against the fleeing accused started raids for his arrest.