August 18: Head Constable Bansi Dhar is found murdered outside a police post near IIT Flyover. He had been shot in the head and robbed of his service revolver.

August 28: Head Constable Kamruddin was shot in the head outside a police post in Moti Bagh. His colleague, constable Manoj, suffered serious head injuries. Kamruddin had also been robbed of his pistol.

August 28: SPG personnel Sivadasan was shot at and robbed of his Maruti car near Malviya Nagar. His car was later found abandoned in R K Puram.

August 29: Three youths were robbed of their Maruti car at gun-point in Malviya Nagar. The car was found abandoned near Aurobindo College on September 12.

September 1: A corporate executive was robbed of his Maruti Esteem. Next day, the car was found in Sector-3, RK Puram.

September 7: A eunuch was shot at near Hyatt Regency.

The suspect is called the ``cop killer-turned-psychopath''. But, probably, he will never be caught: some investigators have given him up for dead. ``Hecould have been a drug addict,'' says one of them nonchalantly, ``and died of an overdose''.

Initially, senior officers insisted that both their colleagues were hit-and-run victims. Constable Manoj's statement and post-mortem reports, however, proved them wrong. Both were shot with the same .455 caliber revolver, a weapon available only with Delhi Policemen. Bansi Dhar and Kamruddin died, Manoj was lucky to survive.

Then the same senior officers concluded that a cop-killer was on the prowl. And the cop-killer robbed revolvers. The killer, they said, must have robbed or stolen the .455 revolver. ``But he isn't an ex-policeman,'' asserted one official.

The cop killer became a psychopath one month later, but only after two more cases of attempt to murder and three cases of robbery in September. In these cases, the victims were civilians. But the same weapon was used to threaten or injure them. The south-west Delhi Police, who are conducting the investigations, then reluctantly agreed that all theincidents, including the attacks on their colleagues, were connected.

Now, eight months after it all began, investigations are heading nowhere. Once, in January this year, the police claim they nearly caught him. But he slipped away.

Investigators then began ``analysing the suspect's psyche and his motive''. Says a senior official: ``We concluded that he was probably a victim of police excesses. And therefore he bore a grudge.''

There were more conclusions: since almost all the cars he had robbed were found abandoned in the RK Puram area, he probably lived close by. Besides, most of the victims were also attacked in and around RK Puram. They are yet to find his address in RK Puram.

The police prepared his portrait, based on the description given by the victims. Constable Manoj, who has rejoined work, says he vaguely recalls his assailant. ``It all happened in a flash. I don't even remember how he came and how he left. But I did catch a glimpse of his face,'' he says.

Others like SPG personnelSivadasan, who was shot at and robbed of his Maruti car from near Malviya Nagar on August 28, caught more than a glimpse. Sivadasan was attacked an hour after Head Constable Kamruddin was shot dead in Moti Bagh. But Sivadasan saw his assailant's face before the later opened fire and drove away in his Maruti car.

The police describe the suspect as a very fair, thin youth with grey eyes and 5'7'' tall. And he is usually seen wearing a loose shirt and blue jeans. One of his victims recalled seeing him wearing a sports cap.

Armed with his portrait, the police scoured the Capital and even neighbouring states like Rajasthan and UP. But without success. On one occasion, two `enthusiastic' constables beat up a Doordarshan production assistant, mistaking him for the cop-killer.

Then, in January this year, when all leads started drying up, some investigators announced that the suspect could be dead. ``He has never been spotted since January, there have been no further attacks,'' says an investigating officer.Investigations, even into the murder of their own colleagues, apparently can take a back seat, probably till another similar incident occurs.