Why women kill, and why ‘Last Kiss’ was difficult to write

Writing about a fictional female killer has its challenges and, as I discovered, requires a whole separate body of research to back it up, particularly if you want to create a strong, three-dimensional lady killer. For a start, I needed to look at how women kill, why they kill, how it differs to their male counterparts, how it has changed over time and finally the level of gender bias that exists.

We know statistically women will commit murder less often than men. In a study done by the United States Department of Justice on murders between 1980 and 2008, 90 per cent of the killings were attributed to males. This doesn’t come as any surprise, as all the evidence seems to point to women being less physically aggressive and generally more inclined to assume a nurturing role in society.

We also know that very often the reasons why women kill are different. They rarely kill strangers, and many conflicts arise out of domestic violence happening within the four walls of home, perhaps after years of abuse. There is also the femme fatale interpretation, crimes of passion, along with simple self-defence, or tragically the killing of family members because of an underlying mental condition. However, domestic and psychological abuse or a debilitating mental condition are not the only reasons women kill. And in many cases, there would appear to be a strong emotional surge behind a woman deciding to kill. That being said, they can certainly be as hard and deadly as their male counterparts, and at times more creative.

One of the reasons for this creativity is the physical differences between males and females. Sometimes women need to compensate for their lack of physical strength, and this can be done by reducing their victim’s defences. In the past, the use of poisons was the preferred choice of killing for many female killers. This not only compensated for any physical deficiency; it also meant the woman didn’t have to see her victim die. Another method of killing is the use of a knife. The frequency of use of this weapon has increased over time, and it is very different to the seemingly ladylike act of poisoning a victim. This is probably a distinctly European feature, with firearms more commonly used in the US.

Also, there is a body of research which suggests that females are not necessarily less aggressive than men, but rather they tend to show their aggression in a more covert and less physical manner. The jury is still out on that one, but what we do know is that men have the greater potential to be violent, brutal and aggressive, and indeed, arguably, because of that, are freer to display it, whereas in contrast, at times, it would appear, women are supposed to behave as if it doesn’t exist within them.

While writing Last Kiss, one of the areas of research that surprised me was how difficult it can be for society to accept that women kill unless there are enormous mitigating circumstances. Feedback from police and the judicial system would indicate that it is much harder to secure the conviction of a female suspect than a male. In part we don't want to believe that the fairer sex could commit such an act and, if they do, we want there to be a very good reason for it.

Interestingly enough, when the guilt of a woman is beyond doubt, when those beliefs around women being gentler, kinder, more nurturing are violated, people can react with utter rage. An Irish example is Catherine Nevin, nicknamed the Black Widow, or Charlotte and Linda Mulhall, deemed the Scissor Sisters. Similarly, when the two little girls, Holly Wells and Jessica Chapman, were murdered in Soham some years ago, there seemed to be as much rage directed at Maxine Carr, the female partner of the killer, for not doing anything, as for the killer himself. Maxine didn't fulfil the "typical" female role of someone who protects children. She contradicted our concept of the nurturer and our heightened anger towards her was in part based on our social bias.

There have also been a number of studies conducted which looked at the suggested cause of gender difference in aggression, including mechanisms such as biological predispositions, particularly the greater level of testosterone in men; social learning; reactions to provocation; patriarchal attitudes and gender roles, but one area that particularly spiked my interest was the role of emotional arousal and how it influences the level of aggression used.

In scientific terms, emotional arousal is defined as a physiological response, an energising, excitatory mechanism associated with heightened activity in the autonomic nervous system. Importantly, researchers have linked this to aggression and their findings suggest that the higher one’s emotional arousal is, the more likely one is to behave aggressively. Evidence suggests that males are more quickly and easily aroused by relatively strong stimuli, and take longer to return to baseline levels than females.

In general terms, males are also socialised into thinking that anger is acceptable to show, whereas sadness isn’t, therefore men tend to react to any physiological response with anger and act accordingly, whereas women tend to have more social “permission” to be sad or upset.

Whatever the statistics tell us about female killers being in the minority, what is undeniable is that on an individual basis, a female killer can do as much physical damage as a man and, depending on particular circumstances, a weaker person can inflict huge damage on someone stronger.

Writing fiction can be tricky. You are telling a story, albeit a fictional one, and although the reader knows this isn't real life, whilst being sucked into a novel, and in the case of Last Kiss, a psychological crime novel, everything about the characters and plot have to stand up.

I knew my female fictional killer wasn’t going to kill in self-defence or due to any obvious mitigating circumstances. I also knew she would behave differently to a male killer, think differently, and that she would be capable of doing bad things – at odds with social norms and our perceptions of the female nurturer. This ran the risk of her being loathed by the reader because of potential social bias.

I didn’t need the reader to agree with the killer’s actions, far from it, but I did want them to be drawn to her, to want to know more about her, and rather than being offended and enraged by her contradiction of the female carer, to be pulled into the why of the story.

If there is an overall strand running through Last Kiss, it is nature versus nurture, and the fallout for humanity when nurturing goes badly wrong. When it does, it very often creates generational damage, and in the fictional story of Last Kiss, fairly quickly it becomes apparent that regardless of gender, human beings are capable of inflicting great harm and damage on each other if the environmental, physical and psychological circumstances allow it.

Louise Phillips is an author of three psychological crime thrillers. Her debut novel, Red Ribbons, hit the bestseller list in the first week of release and was shortlisted for the Irish Crime Novel of the Year 2012 in the Bord Gais Energy Irish Book Awards. Her second novel, The Doll's House, won the award in 2013. She has won the Jonathan Swift Award, was a winner in the Irish Writers' Centre Lonely Voice platform, and her writing has been shortlisted for prizes such as the Molly Keane Memorial Award and Bridport UK. Last Kiss (Hachette Ireland, £12.99) is her third novel and she is currently working on her fourth.