The idea of a serial killer in our midst has long been a source of morbid fascination. That there are people capable of such evil appals and excites the general public in equal measure. It's the stuff of nightmares. Ultimately, it captivates us because the horror is abstract and unreal: most of us will never come in contact with a serial killer.
In Ireland, the closest glimpse we've had of men capable of multiple murders were Englishmen John Shaw and Geoffrey Evans. Both were convicted of the rape and murder of two young women, Elizabeth Plunkett and Mary Duffy, in Mayo in 1976. Shaw remains in prison while Evans is on a life-support machine at Dublin's Mater hospital under prison guard.
And while these men no longer pose a threat and are therefore not feared by the public, the same cannot be said of Larry Murphy, who has long been suspected of being Ireland's only serial killer, despite the fact that he has never been convicted of murder. While the speculation is not unfounded, nothing is proven. Because suspicion has engulfed the convicted rapist, Murphy's release from prison last week generated unprecedented media coverage.
There are numerous examples of serial killers worldwide. Considering Ireland's population, statistically it is surprising we do not have a convicted serial killer behind bars with several murders under his belt. And it is usually men: in 90% of serial murders, men are the perpetrators. While there have been female serial killers acting alone, in many cases they get involved at the behest of domineering male partners. This was the case with the Moors murders in Manchester in the 1960s. Ian Brady and Myra Hindley killed five children before they were caught. Initially at least, Hindley was under the influence of her boyfriend.
Defining the 'characteristics' of a serial killer is like defining the length of a piece of sting. Generally speaking – but this is true of most people who commit serious, violent crimes – there are problems in their family background that caused them to become highly dysfunctional.
"Serial killers do have certain broad characteristics. You would not know a serial killer if they were sitting next to you," explained Dr Tod Burke, a professor of criminal justice at Radford university in the US and a former policeman. Burke has published extensively on serial killers.
"They do not stand out," he said. "They are charmers, often charming their way into people's lives. They blend in extremely well. It is a myth that they are stereotypical loners. You or I would never suspect that person. For a serial killer, the first murder is the hardest for them. But once they get away with it, they want to do it more and more. That's when they begin to get sloppy; they believe they can get away with it. It's then they begin to tease the police and sometimes leave deliberate clues. It's not always the case that they continue until they get caught: many of them just stop and we don't know why. One example is Jack the Ripper in England."
One British serial killer who seemed incapable of stopping was Dr Harold Shipman. He was jailed for life in January 2000 for murdering 15 patients while working in Manchester. An official report later concluded the GP had killed between 215 and 260 people over 23 years in West Yorkshire. He hanged himself in prison in 2004.
Shipman may have been the UK's most prolific convicted serial killer but the fascination with Jack the Ripper has always been huge, mainly because he was never caught.
"For serial killers, it's very personal why they kill. There is always some kind of pattern. Sometimes it's a sloppy pattern, other times it's precise but they are never without some form of pattern. There is a symbolic reason why they kill," said Burke. "The motivation of a serial killer is very specific to that person. Some might only kill blondes, others might only murder hitchhikers. Some focus on victim occupations, such as prostitution, while others might go for senior citizens or children."
One man who did not fit the profile of the stereotypical serial killer was Ted Bundy. One of the most notorious murderers in history, he was responsible for the rape and murder of several women between 1974 and 1978 in the US. An educated and charming young man, sometimes he raped his victims before killing them. In other instances, he murdered the women first and raped them afterwards. His method of killing was either strangulation or bludgeoning. He was arrested in 1975 but escaped within 17 hours of his capture. He was arrested again in 1978. In January 1989, Ted Bundy was sent to the electric chair.
"One of the most fascinating things about serial killers is they can be so different. We focus on them because they are exciting and rare," added Burke. "They can beat a polygraph exam no problem. They can make themselves believe they didn't do it. Lying becomes a way of life for them. Some of them never admit what they have done, even after they have been convicted."
The method of Larry Murphy's infamous crime – how he carried out the abduction, rape and attempted murder of the young Carlow woman – suggested to detectives he was a seasoned predator. Over the decade he spent in prison, he has never shown any remorse. He is a man with an appetite to kill who has refused various offers of rehabilitation for sex offenders. He has never explained his actions. No one – not the country's most senior gardaí or his family – seems to have any real understanding of what goes on inside his mind. Senior gardaí say he is one of the most perplexing criminals they have ever met.
'Getting into his head' has been impossible because he would not engage on any level. He refused to interact with gardaí when they came in to question him after the disappearance and suspected murder of three other women in the Leinster area: Annie McCarrick, Jo Jo Dullard and Deirdre Jacob. A detailed background investigation by detectives since Murphy's arrest and conviction has revealed a confident, calculating attacker.
"What is evident among serial killers is their lack of empathy. They cannot put themselves in their victims' shoes," said Jonathan Culleton, a lecturer in sociology and criminal justice at Waterford Institute of Technology's (WIT) centre for social and family research. "This is often coupled with a cold, rational intelligence. Larry Murphy certainly seems entirely emotionless over the crime he was convicted of carrying out.
"If he is responsible for the abduction and murder of those three other women, it is quite an achievement to disappear three women without a trace. The thought, planning and calculation that would go into that is disturbing. To become a serial killer requires detachment. We obviously don't know if Murphy is responsible for these other crimes. But his apparent detachment and the calculating attack he was convicted of terrify people."
That the carpenter from Baltinglass refused to undergo any rehabilitation is a major cause for concern. In some other jurisdictions, people who are convicted of rape are not allowed out of prison unless they have rehabilitative therapy.
"It is odd that he would refuse any attempt at therapy. If a psychotherapist ever got near him, that might be it for Larry Murphy," said Culleton. "Possibly he has never faced up to his crimes or was afraid about what he might say. The scary thing about this guy is that we know so little. The criminal justice system knows virtually nothing about him. He is still very much a mystery. When we don't know much about someone like this, we fear the worst."
There has never been any suggestion that there was anything out of the ordinary about Murphy's upbringing, that he suffered any major trauma such as parental abandonment, a common characteristic among serial killers and violent criminals. But we don't know a huge amount about his early life.
"He clearly has an incredibly strong hatred of women. Where is this coming from?," asked Culleton. "It is easy to label someone as a suspected serial killer, especially when they have another serious conviction. But what made him what he is? What happened to Larry Murphy?"