Lucy Letby is currently in jail after being convicted of the murder of seven babies, and attempted murder of a further seven, while she worked as a neonatal nurse at the Countess of Chester Hospital.

The crimes levelled against Letby shocked the nation as did the growing call for a retrial following criticism of the circumstantial evidence used to convict the 35-year-old.

She gained further support in the bid to prove her alleged innocence after a 13,000-word article was published in the New Yorker magazine highlighting concerns about Letby’s trial, which was prohibited from being published in the UK due to a contempt of court order.

One of the main points raised in any argument against the conviction of Letby is the apparent lack of a clear motive for her to have committed such heinous crimes – something which is being asked as the Criminal Cases Review Commission considers submissions from the convicted child killer’s new defence team.

With this review still ongoing, here are five crucial questions which may cast doubt on Letby’s conviction:

1 – What was her motive?

It is widely believed that serial killers often carry motives for the crimes they commit, with their evil actions often being linked to previous events in their lives or beliefs.

Yet, there appears to be no set modus operandi for Letby with her victims dying through various methods such as injecting air into babies’ veins, poisoning them with insulin, forcing air into their stomachs, dislodging a feeding tube and overfeeding them with milk.

Meanwhile, six of the suspicious deaths found were put down to natural causes according to port-mortem reports with the other being unexplained. 

2 – Lucy Letby’s rota

A work rota presented to the jury was deemed a major factor in Letby’s conviction as it appeared to place her on shift at the time of 25 deaths and collapses.

The 37 other nurses at the Countess of Chester Hospital were on duty for only a handful of cases each.

However, police documents presented since note that the prosecution’s chief expert witness, Dr Dewi Evans, had looked at 28 cases of suspicious incidents beforehand with Letby being absent for 10 of them.

The jury was informed of these other deaths and collapses from the same period. It is also claimed that door-swipe evidence in one of the used cases was incorrect, showing Letby to be on the ward when she wasn’t.

The Royal Statistical Society wrote to the chair of the Thirlwall Inquiry into the Letby case back in September 2023, stating that “it is far from straightforward to draw conclusions from suspicious clusters of deaths in a hospital setting.”

3 – Lack of direct evidence?

Letby was found guilty despite there being no direct evidence from witnesses, forensics, post-mortems or CCTV footage to clearly show she had committed murder.

A single medical witness across Letby’s two trials was able to attempt to directly link the convicted nurse to the babies’ deaths – this was given by Dr Jayaram.

But, his account has since been called into question after testifying that Letby was standing over Baby K’s cot as the girl was deteriorating but failed to alert help.

A recently unearthed email, previously undisclosed to her defence, may show Letby did attempt to call him for help.

“‘At time of deterioration . . . Staff nurse Letby at incubator and called Dr Jayaram to inform of low saturations [of oxygen levels],” it reportedly states.

4 – How was guilt proven?

Those who believe in Letby’s innocence raise the possibility that the number of deaths dropped due to the Countess of Chester neonatal unit being downgraded in 2016 rather than Letby being removed.

They argue that because the unit could no longer accept critically ill babies delivered at less than 32 weeks or in need of intensive care, due to being downgraded, fewer deaths occurred there.

In 2016, the Royal College of Paediatrics reviewed the spike in infant deaths and blamed the standards of neonatal care in the unit over a substantial period due to issues such as being understaffed and under-resourced.

5 – Post it note confession

A seemingly ‘Gotcha’ moment came when the prosecution presented therapy notes written by Letby after she first heard of the accusations.

One of these notes was scribbled “I am evil” and presented as a confession. Letby’s defence counters that the notes are more an expression of guilt for failing to save the lives of ill children rather than admission to murder.

Other notes read, “Why me? I haven’t done anything wrong” and “I am not good enough to care for them.”