Netflix’s “The Investigation of Lucy Letby” Left Out the Evidence That Could Prove Her Innocence

Lucy Letby is serving 15 whole-life orders at HMP Bronzefield for murdering 7 babies and attempting to murder 7 more at Countess of Chester Hospital between 2015 and 2016. She is the most prolific child serial killer in modern British history.

But in 2025, an international panel of 14 neonatologists concluded there was “no medical evidence to support malfeasance” and that the babies likely died from natural causes or poor medical care. Hundreds of doctors and scientists now say the evidence used to convict her is wrong.

The Criminal Cases Review Commission is actively reviewing her case as of February 2026.

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On August 21, 2023, Lucy Letby was convicted of murdering 7 babies and attempting to murder 7 more at Countess of Chester Hospital.

The prosecution called her the most prolific child serial killer in modern British history.

She received 15 whole-life orders, meaning she will die in prison.

The jury heard that Letby injected air into babies’ bloodstreams, poisoned them with insulin, and overfed them through feeding tubes.

They heard that she was present for all 25 suspicious incidents on the neonatal unit.

They heard about handwritten notes found in her home that said “I am evil I did this.”

What the jury did not hear: hundreds of doctors and scientists now say the medical evidence used to convict her is wrong.

In May 2024, The New Yorker published a 13,000-word investigation questioning the conviction.

In February 2025, an international panel of 14 neonatologists, including the doctor whose research was used to convict Letby, held a press conference stating there was “no medical evidence to support malfeasance.”

By 2026, the case has become one of the most controversial convictions in British legal history.

On February 4, 2026, Netflix released The Investigation of Lucy Letby, bringing the case to a global audience and reigniting the debate over her guilt.

This is the evidence the experts say doesn’t add up.

The Neonatal Nurse Convicted of Murdering 7 Babies

Lucy Letby was born on January 4, 1990, in Hereford, England. She was the only child of John and Susan Letby.

Her upbringing was described by neighbors and investigators as stable and conventional. There were no behavioral red flags, no history of abuse, no social isolation.

She studied nursing at the University of Chester from 2008 to 2011 and began working at Countess of Chester Hospital in January 2012.

By 2015, she had completed advanced neonatal training and was considered a specialist in intensive care.

Colleagues described her as extraordinarily hard-working, often volunteering for overtime and night shifts.

Eirian Powell, the neonatal unit manager, called her “flexible” and “dedicated.”

Before June 2015, there were no documented complaints about her clinical performance or professional conduct.

She was regarded as a trusted and integral member of the neonatal team.

In 2013, she was even chosen as the “poster girl” for the hospital’s newborn appeal fundraising campaign.

The 13 Months When 17 Babies Died

Between June 2015 and June 2016, the neonatal unit at Countess of Chester Hospital experienced a spike in deaths.

Seventeen babies died in 13 months, compared to a baseline of 2 to 4 deaths per year.

The unit was a Level 2 facility, designed to care for moderately ill babies born from 27 weeks gestation.

But during this period, the unit was operating under extreme pressure, often exceeding its capacity and treating babies who should have been transferred to Level 3 tertiary centers.

The Thirlwall Inquiry, which released testimony in 2025 and 2026, revealed significant environmental failures.

The unit was located in a 1960s-era building with deteriorating infrastructure.

Lorenzo Mansutti, a hospital plumber, testified that raw sewage was backing up into handwash basins in Nursery 1, the intensive care nursery where the most vulnerable infants were treated.

A Pseudomonas aeruginosa outbreak was identified on the unit during the same period. This antibiotic-resistant bacterium has a documented mortality rate of 55% in low-birth-weight neonates.

The unit was chronically understaffed, with nursing and doctor vacancies throughout 2015 and 2016.

The Doctors Forced to Apologize to Lucy Letby

In July 2015, after the deaths of several babies in June, Dr. Stephen Brearey, the unit’s lead consultant, first raised concerns about Lucy Letby.

Dr. Ravi Jayaram, another consultant, also expressed suspicions.

The doctors noticed a pattern: babies were collapsing unexpectedly when Letby was on shift.

But hospital executives, including CEO Tony Chambers and Medical Director Ian Harvey, did not take these concerns seriously for nearly two years.

Documents revealed by the Thirlwall Inquiry in February 2026 show that managers were worried about “potential media attention” if police were involved.

In an extraordinary turn of events, management initially sided with Letby.

After she raised a grievance, the consultants were forced to write her a formal letter of apology.

Letby was removed from clinical duties in July 2016 and redeployed to a clerical role.

But police were not contacted until May 2017, nearly two years after the first deaths.

The Air Embolism Theory That Convicted Her

The prosecution, led by Nick Johnson KC, alleged that Letby used various methods to murder infants.

The primary theory was venous air embolism. Prosecutors claimed Letby injected air into babies’ intravenous lines, causing rapid cardiovascular collapse and death.

The key expert witness was Dr. Dewi Evans, a retired consultant pediatrician.

Dr. Evans reviewed cases of unexpected collapse and concluded that skin discolorations observed on babies like Child A, Child D, and Child E were evidence of deliberate air injection.

Witnesses described “patchy,” “bright pink,” or “purple” skin discolorations.

Dr. Evans cited a 1989 research paper by Dr. Shoo Lee to support his claim that these marks were diagnostic of air embolism.

The prosecution also alleged insulin poisoning in two cases, Child F and Child L.

Blood test results from Liverpool Clinical Laboratories showed extremely high insulin levels paired with suppressed C-peptide levels.

The prosecution argued that because the body produces C-peptide in equal amounts to insulin naturally, a high-insulin/low-C-peptide ratio can only be explained by synthetic insulin injection.

The jury was told there was “no doubt” these were poisonings.

Finally, the prosecution presented a shift pattern analysis showing that Letby was the only staff member present for all 25 incidents included in the investigation.

Nick Johnson KC described the pattern as “self-evidently obvious” and a “process of elimination.”

The I Am Evil I Did This Notes

When police searched Lucy Letby’s home, they found handwritten notes.

One note said: “I am evil I did this.”

Another said: “I killed them on purpose because I’m not good enough.”

The prosecution interpreted these as confessions.

The defense argued they were expressions of mental breakdown, written by someone being accused of unthinkable crimes and struggling to process the trauma.

The jury sided with the prosecution.

The August 2023 Guilty Verdicts on 14 Counts

After a 10-month trial at Manchester Crown Court, one of the longest in UK history, the jury convicted Lucy Letby of 7 murders and 7 attempted murders.

The murdered babies were Child A, Child C, Child D, Child E, Child I, Child O, and Child P.

The attempted murder victims were Child B, Child F, Child G, Child L, Child M, Child N, and later Child K.

She was acquitted on two counts involving Child H and Child J.

The jury was unable to reach verdicts on six other counts.

Mr. Justice Goss sentenced her to 15 whole-life orders, meaning she would never be eligible for parole.

In July 2024, she was retried for the attempted murder of Child K and convicted again.

Netflix’s The Investigation of Lucy Letby and What It Didn’t Show

On February 4, 2026, Netflix released The Investigation of Lucy Letby globally.

The documentary presented the prosecution’s case, including the shift pattern analysis, the handwritten notes, and testimony from medical experts like Dr. Dewi Evans.

What the documentary did not show was the growing international movement of medical experts questioning the conviction.

It did not include the February 2025 expert panel findings or the challenges to the statistical evidence.

It did not detail the hospital’s environmental failures, the Pseudomonas outbreak, or the raw sewage backing up into handwash basins.

And it did not mention that Dr. Shoo Lee, whose research was used to convict Letby, would later say his paper had been misinterpreted.

The New Yorker Investigation That Changed Everything

In May 2024, The New Yorker published a 13,000-word investigation by Rachel Aviv titled “A British Nurse Was Found Guilty of Killing Seven Babies. Did She Do It?”

The article was initially geoblocked in the UK due to a court order intended to prevent prejudice against the upcoming Child K retrial.

Aviv’s reporting highlighted several critical flaws in the prosecution’s case.

First, the statistical analysis failed to account for Letby’s high number of hours worked compared to other staff.

Letby worked 30 to 50% more shifts than the average nurse and was frequently assigned to the most critical patients because of her advanced training.

Second, the systemic problems at the hospital, including the Pseudomonas outbreak and sewage leaks, offered viable alternative explanations for the deaths.

Third, the case bore striking similarities to Lucia de Berk, a Dutch nurse wrongly convicted of murder in 2003 based on flawed statistical shift analysis. De Berk was exonerated in 2010.

The 14 Neonatologists Who Say No Medical Evidence

On February 4, 2025, an international panel of 14 clinicians held a press conference to release a report challenging the convictions.

The panel was chaired by Dr. Shoo Lee, the author of the 1989 paper that Dr. Dewi Evans had used to support the air embolism theory.

The panel included neonatologists from the UK, US, Canada, Germany, Japan, and Sweden, as well as specialists in infectious disease and pediatric surgery.

Their conclusion: there was “no medical evidence to support malfeasance” and the deaths were likely the result of “natural causes or just bad medical care.”

Professor Neena Modi of Imperial College London stated that the infants were “overtly unwell or at high risk of developing complications” and that the jury reached their verdict on “incomplete and misleading” information.

The Researcher Whose Paper Was Misinterpreted

Dr. Shoo Lee, founder of the Canadian Neonatal Foundation, testified in 2025 that his 1989 paper had been “misinterpreted” by Dr. Dewi Evans.

Lee clarified that the skin discolorations diagnostic of air embolism in his research were not the same as those described in the Letby trial.

He noted that the “patchy” discoloration described by witnesses was more consistent with hypoxia (lack of oxygen) or post-mortem changes than with the specific patterns caused by venous air embolism.

Furthermore, radiologists have noted that the presence of gas on infant X-rays is a common finding following resuscitation attempts and cannot be used as definitive proof of deliberate harm.

The Insulin Tests Experts Say Were Wrong

Experts in biochemistry and bioengineering, including Professor Geoff Chase of the University of Canterbury, have challenged the insulin poisoning convictions for Child F and Child L.

A 100-page study released in 2025 concluded that the data presented to the jury was “inconsistent” with poisoning.

The immunoassay tests used by the hospital laboratory were not of “forensic quality” and are known to give false positives due to antibody interference.

Standard medical protocol for a poisoning diagnosis requires a secondary, more specific test, such as mass spectrometry, which the hospital failed to perform.

Experts also noted that C-peptide levels in neonates are naturally low and that the “abnormally high” insulin results were physiologically inconsistent with the lack of severe clinical symptoms, such as seizures or heart arrhythmia, in the infants.

The Statistical Fallacy That Convicted Lucy Letby

The shift pattern evidence has been a major target for statisticians.

Professor Norman Fenton of Queen Mary University London and Dr. Michael Hall have argued that the prosecution’s correlation table was an example of the “Prosecutor’s Fallacy” and selection bias.

The investigation “started at the target” and worked backward.

Consultants first identified Letby as a suspect based on a gut feeling, then selected which deaths were “suspicious” based on her presence.

Professor John O’Quigley demonstrated that if all deaths on the unit during the period were included, not just those where Letby was on duty, the correlation vanishes.

There were at least ten other deaths during the same period where Letby was not implicated, yet these were not classified as “suspicious” and thus not shown to the jury.

Statisticians have explained the “Letby effect” through Simpson’s Paradox, a phenomenon where a trend appears in several groups of data but reverses when the groups are combined.

Letby worked 30 to 50% more shifts than the average nurse and was frequently assigned to the most critical patients.

A nurse working more hours in the highest-risk room is mathematically more likely to be present at the time of a random or natural collapse by chance.

When adjusted for her higher shift count and patient acuity, Letby’s presence at the collapses was statistically unremarkable.

The Wrongful Convictions Based on Bad Statistics

The Lucy Letby case is frequently compared to two major miscarriages of justice involving medical professionals and statistical evidence.

Sally Clark was a British solicitor convicted in 1999 of murdering her two infant sons based on expert testimony from Sir Roy Meadow, who claimed the probability of two sudden infant deaths in one family was 1 in 73 million.

This statistic assumed the deaths were independent events and ignored genetic and infectious factors.

Sally Clark was exonerated in 2003 after spending three years in prison. She died in 2007 from alcohol poisoning, her life destroyed by the wrongful conviction.

Lucia de Berk was a Dutch nurse convicted in 2003 of multiple murders based on shift pattern analysis.

Prosecutors claimed there was a 1 in 342 million probability that her presence at deaths was coincidental.

The statistical analysis ignored confounding factors and used skewed data.

Lucia de Berk was exonerated in 2010 after serving six years in prison.

Experts argue the same flawed statistical logic was used against Lucy Letby.

Where Lucy Letby Is Now in 2026

As of February 2026, Lucy Letby is serving 15 life sentences at HMP Bronzefield in Surrey, the UK’s largest women’s prison.

Reports describe her as a “model prisoner” who maintains a neat cell and works as the prison librarian.

Despite her status, she is a high-risk Category A inmate.

Staff must actively protect her from other prisoners who view her crimes with hostility.

She remains in a high-security unit, and her social visits are conducted under strict supervision.

Her parents, John and Susan Letby, have remained fiercely loyal and visit her regularly.

The Appeal That Could Free Her

In early 2025, Lucy Letby’s new legal team, led by barrister Mark McDonald, submitted an application to the Criminal Cases Review Commission (CCRC).

The CCRC is an independent body that investigates potential miscarriages of justice in England, Wales, and Northern Ireland.

The application includes new evidence from the international expert panel and independent reviews of the insulin and air embolism evidence.

On February 3, 2025, the CCRC received the preliminary application.

On March 31, 2025, initial expert reports were received.

On May 2, 2025, main legal submissions and expert reports were filed.

On December 11, 2025, defense materials and waiver of legal privilege were received by the CCRC.

On January 21, 2026, further expert reports on insulin and statistics were submitted.

As of February 2026, the CCRC formal review remains active and the case is being prioritized due to public interest.

The CCRC must determine if there is a “real possibility” that the Court of Appeal would not uphold the convictions.

This threshold usually requires fresh evidence that was not heard during the original trial, such as the 2025 expert panel’s findings.

Serial Killer or Scapegoat The Unresolved Question

As of February 2026, the question remains unresolved.

The families of the babies largely maintain their belief in her guilt and have expressed distress over the expert criticism.

But a significant portion of the public and the scientific community now views the case with skepticism.

In January 2026, the Crown Prosecution Service decided not to bring further charges for nine additional babies.

This decision was seen as a pivot point, suggesting that the evidential standard used in the first trial might not have been robust enough for further scrutiny.

The decision drew criticism from Cheshire Constabulary, which maintained that their evidence met the charging standard, exposing a rift between police and the prosecution service.

Several central questions remain.

If Letby is innocent, what caused the spike in deaths? Experts point to a “perfect storm” of a Level 2 unit being forced to act as a Level 3 unit, combined with chronic understaffing, sewage contamination, and the Pseudomonas outbreak.

Why was Dr. Dewi Evans, a general pediatrician with a history of judicial criticism, selected as the lead expert for a neonatal case?

Why did the original defense team call no medical experts, despite instructing multiple specialists during trial preparation?

Why were forensic autopsies not ordered at the time of the deaths if consultants truly suspected foul play as early as 2015?

The case represents a collision between the clinical realities of a failing NHS unit and a legal system that often struggles to process complex, multi-variable scientific evidence.

Whether Lucy Letby remains behind bars or becomes the subject of the UK’s most high-profile exoneration depends on the CCRC’s ability to weigh the “extraordinary coincidence” of her presence against the “highly plausible” alternative causes of death identified by the world’s leading neonatologists.

As of February 2026, the case remains one of the most significant and unresolved controversies in modern legal history.

Lucy Letby: Frequently Asked Questions