AN auxiliary policeman stabbed to death in Shekkipmei this month was probably killed by a fellow officer, detectives believe. They say Ng Ka-wing, 29, was attacked by two men and apparently knew at least one of them. A police source said last night: ''All the evidence points to one of the men who attacked and killed Ng being a police officer.'' Ng was stabbed to death on September 12 while patrolling Pak Tin Estate, Shekkipmei. ''It appears Ng was killed by someone who was out to murder him, and all the evidence, which was found in a purple-edged travel bag at the scene, indicates a police officer was involved,'' the source said. Apart from containing a police issue speed-loader - of the type used by the CID - the bag also held a pouch with an additional four bullets, and a piece of material known as a ''four by two'' which police use to clean the barrels of service revolvers. ''It is very unlikely a member of the public or a typical criminal would be carrying this type of equipment,'' the source said. ''Adding to our belief that one of Ng's killers was known to him and appears to be a police officer is the fact that Ng didn't pull his emergency assistance cord. ''Pulling the emergency cord is like flicking a switch and takes less than a second to do. Once activated, it alerts other police and opens up a radio channel which would pick up the noise from the scene. ''As Ng didn't do this it seems highly probable that he recognised his eventual attacker or attackers and didn't feel threatened. He didn't pull his revolver either so it appears he didn't think he was going to be attacked,'' the source said. Ng died from multiple stab wounds to the head, neck and chest. ''Our investigations indicate Ng was still writing in his log book when he was attacked and he then put up a desperate struggle,'' the source said. ''It looks as though he was held from behind while being stabbed, and the blood patterns tell of a fierce fight during which one of Ng's attackers may have been injured and the purple sports bag had its strap broken. ''The frenzied attack on Ng also indicates his killer or killers planned to murder him, as an opportunist or random attack would very rarely, if ever, feature such vicious multiple stabbings. It looks like whoever murdered Ng really wanted him dead.'' However, motives for the attack and detailed leads on the killers' identities have eluded police. ''Ng was a well-respected, quite responsible man with no huge debts or known enemies so it is difficult to pin-point individuals who may have wanted him dead,'' the source said. ''We have issued one photofit image of a suspect who is described as about 30, 1.7 metres tall and heavily built. Anyone with further information associated with Ng's murder is urged to call police.''