Profile of a killer: 'He is consumed with being recognised'

We call him a madman, but there is method in this killer. When he strikes, he only fires one bullet. He uses the same .223-calibre weapon every time. When the authorities build up their forces in one region, he shifts to another. But he always stays within a 35-mile radius of Washington DC.

By using the same gun, he is making sure of one thing: that the police know quickly, once the ballistic analysis of the bullet has been completed, that each killing is his handiwork. And he has communicated with his pursuers directly, with a tarot card left at the scene of one murder.

But he is not ready to get caught. Not yet anyway. For now, this is a deadly cat-and-mouse game he is playing. The first six victims were killed in congested commercial areas, where a fast getaway was difficult.

Now, his strategy has shifted. He has ensured that his last four targets have been at locations close to major highways, ensuring a fast getaway.

And always, he has chosen people who are clearly exposed and easily hit.

They are standing immobilised, filling their cars with petrol, or sitting on a bench. That makes success easier with a single shot. He only wants the noise of the bullet firing to be heard once, so he can get on his way.

Gary Cooper, an ex-FBI profiler, agrees that this is a man who is thinking carefully.

"Everybody is talking about what kind of insane monster could be doing this," he said yesterday. "But it is important to understand that this individual, while maybe morally insane, is definitely not mentally unstable. He is an anti-social psychopath with no remorse for what he has done. He is narcissistic, he is focussing on his own ego and importance. He is consumed with being recognised for having power. And for the first time in his life he is expressing [this power].

"If the writing on the tarot card is really his, he is expressing an incredible power not just over the victims, but over police and society as well."

If it is confirmed that yesterday's petrol station was also the work of this man, it will underscore his willingness to tantalise his pursuers.

He fired his gun even though a police officer was standing across the street attending to a car accident.

He has tantalised the police before. Now he may have killed right under their noses.

Mr Cooper warned that the media and overwhelming police reaction may be feeding the sniper's appetite. "It is very important how we respond to him," he said. "The constant comments of the state of terror feed his ego. He sees this as accomplishing what he set out to do. He has never received, always craved, attention, he has a black hole for attention, credit and acknowledgement."

Mr Cooper said that the killer is probably a white male, perhaps with military training and certainly a familiarity with firearms. "As to former military training, he was probably a wannabe, never achieved the status he was looking for and was prematurely kicked out," he said.

"He does not want to be caught at this point. But it is a win-win situation if he gets caught," Mr Cooper added.

How will it all end? "He may try suicide by cop."