Why do we find it hard to believe that the smiling nurse Lucy Letby was a serial killer? | Martha Gill

Why do so many people still think Lucy Letby is innocent? It’s worth asking, because last week yet another blow was dealt to the theory. In a retrial of one of the charges against her, Letby was found to have attempted to murder another newborn baby, and handed a 15th life sentence .

In the past 10 months, we have heard less about Letby: reporting has been restricted while the trial was going on. In the meantime, she has all but exhausted the appeals process; her second application was denied. In a ruling published last Tuesday, appeal court judges said none of her legal challenges was arguable, and that the criteria for fresh evidence had not been met.

Still, the idea that Letby might not be guilty lingers in the minds of many. Could this sweet-faced young woman really be a killer? Doubt is expressed online, and in the many podcasts about the case. There was even a 13,000-word essay on the subject in the New Yorker in May. “The modern age has brought a proliferation of conspiracy theories which sprout, spread and fester on social media blogs and on websites,” said prosecuting barrister Peter Skelton KC during this latest trial. “Lucy Letby’s crimes, in particular, continue to be the subject of such conspiracies.”

Disbelief has been a theme of the Letby case. It has clung to coverage in the media. When Letby was first convicted last year, ITV’s This Morning host Rochelle Humes commented that she “ didn’t seem like a typical murderer ”. There is “ a void ” that surrounds this case, wrote Sarah Vine in the Daily Mail . “The normal human mind searches desperately for a reason, an explanation – anything to help rationalise the horror. But with Letby, there is nothing.”

Among police, too, there seemed to be a “void” where a profile-fit might be. Nicola Evans, the detective leading the case, described Letby as “beige”. “There isn’t anything outstanding or outrageous that we found about her as a person,” she said , rather haplessly.

Then there was the disbelief among her colleagues, which allowed the crimes to continue in the first place. A public inquiry is now examining why no investigation was ordered into the mounting toll of unexplained deaths of those under Letby’s care for more than a year after a doctor raised the alarm, and why it took almost another year before executives spoke to the police. “It can’t be Lucy. Not nice Lucy,” one doctor recalls saying, as he confronted the growing evidence.

At the root of much of this bafflement seems always to be the idea that Letby is an unlikely killer in appearance, demeanour and profession. “The smiling nurse with the sing-song name who went to salsa classes is now Britain’s most prolific child murderer,” ran a BBC report “Can anyone make sense of that? I know I can’t.”

Serial killers are indeed rare, and only one in six is female, but insofar as they do exist, Letby fits the profile rather well. In an analysis of US female serial killers published in the Journal of Forensic Psychiatry and Psychology , Marissa Harrison found that they tended to be white, middle class, Christian, in their 20s or 30s, of average intelligence and attractiveness and in a “stereotypically feminine job”, such as nursing. In fact, 39% worked in healthcare. They were far more likely than male killers to only target children. And their preferred methods were covert, such as poisoning. Male killers were flashier and messier: shooting, strangling or stabbing.

There is relatively little public knowledge about female serial killers, and the way they really operate

This lines up with a study by David Lester published in the American Journal of Forensic Psychology , which compared female serial killers with male ones. Women were less likely to drink or use drugs, or have a history of arrests. They tended to kill in the same location – rather than going on random “sprees” – and were more organised. Perhaps as a result, they were much less likely to be caught, and then only after a police investigation. There was also an absence of sexual violence and deviance, unlike their male counterparts. So far, Letby fits the mould.

But there is relatively little public knowledge about female serial killers, and the way they really operate – in stark contrast to the many books and films about male ones. Indeed, there has long been blank resistance to the idea that women could commit these crimes in the first place. Criminologist Eric Hickey, who in 1985 was the first to publish an academic paper on female serial killers, has recalled being told by FBI agents early in his career that such killers did not exist . When in 1988 police found evidence that a landlady called Dorothea Puente had murdered several of her tenants, they declined to label her a serial killer . “They said, ‘Oh, that’s not serial killing,’” Hickey told a reporter. “Of course, it was.”

When female serial killers do catch the public imagination, they tend to be those rare women who kill like men. Aileen Wuornos, a sex worker who in 1989 and 1990 shot strangers in the head and dumped at least one body in a junkyard, attracted obsessive media coverage, and is often referred to – quite incorrectly – as America’s first female serial killer.

But this does not reflect the more common type of female serial killer who looks more like Beverley Allitt, the nurse who murdered four children in 1991, or Reta Mays, the nursing assistant who killed seven elderly veterans in 2017 and 2018, or Amy Archer-Gilligan, the nursing home proprietor who poisoned at least five people between 1907 and 1917. Gilligan is not a household name, but she inspired the play Arsenic and Old Lace , in which repeated murders perpetrated by two little old ladies are played for laughs – the joke being that it seems so unlikely.

When Gilligan was arraigned in 1917, a newspaper remarked that “the spectators wondered how on earth the State Attorney could ascribe such gruesome deeds to so pale and gentle a dove”. When Mays was sentenced, she was the “monster no one saw coming”. If we are to catch the next Letby, we should broaden our minds.

• Martha Gill is an Observer columnist

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