The psychology of a killer

The victims, including Tania Nicol and Gemma Adams, were all local

As police investigate the deaths of prostitutes in Suffolk, speculation has begun to mount about who could commit multiple murders.

Consultant forensic psychologist Dr Ian Stephen has worked on previous serial killer cases and advised the makers of the TV drama Cracker.

He said although there was little information to build up a clear profile of who may have killed these women, it was possible to hypothesise about what the person may be like.

Police have not said they are looking for a serial killer but have said there are similarities in the murder of one of the victims, Anneli Alderton, to the killings of two others, Tania Nicol and Gemma Adams.

Dr Stephen said the suspect was probably male, white, in his late 20s, 30s or 40s, and is someone who probably had been let down by women in his past.

"We need to look at how these crimes are connected," he said.

My worry is that his perception of women will change and he will see any woman who's out on the street at night on their own as a prostitute Dr Ian Stephen

"The victims are prostitutes, they are in the same area - so he could have a particular issue with women whatever origin that is from.

"He maybe had a mother who has let him down, or a mother who has abandoned him," he added.

"In some sense he may have idolised women and then they let him down."

But he also said the killer might believe he is on "some kind of Christian mission... clearing the world of prostitutes".

Whatever his profile, Dr Stephen said the murderer is likely to try to kill more women and believes he is getting out of control.

"It is an obsession - compulsive behaviour - a compulsion that is becoming stronger and stronger.

"My worry is that his perception of women will change and he will see any woman who's out on the street at night on their own as a prostitute."

Film-maker and criminologist Roger Graef told BBC Five Live he also believes the killer may have had negative experiences with women in the past.

He said: "You can calculate if it's prostitutes that it's somebody who was damaged by a woman, who is ashamed of his own impulses possibly, who is, you know, a religious zealot, who feels that they're corrupting the whole of mankind."

He added: "When you're talking about somebody who is that ill, it's very hard, really, to speculate intelligently about that until we know a lot more about them."

Generalisations difficult

Professor David Canter, from the Centre for Investigative Psychology, said that while "almost certainly" the killings were the work of one individual, there were too few details yet to form a detailed profile of the suspect.

"It is difficult to assume anything at the moment without a lot more detailed information," he told BBC Newsnight.

He said because serial murders are rare, it is difficult to generalise about the killers involved.

"The two or three individuals that come to mind have all been rather disturbed but they have very different characteristics.

"Some of them found their way into these sorts of murders really from a life of crime where they just become ever more extreme in their criminal acts and in their violence."

Some serial killers also have a "bizarre understanding of the nature of women" and may attack women because they believe they are "seductresses who destroy their virtue", he said.

But, he added it was more likely that the case would be solved by using police records to try to discover where the suspect may be based rather than building an "intense personal description of the offender".