Lucy Letby: Investigating the UK's most prolific child killer

It was the outpouring of 2017 erstwhile an alarming missive arrived astatine Cheshire Police's headquarters, addressed to the main constable.

It was from the main enforcement of the Countess of Chester Hospital, which had seen an unexplained surge successful deaths and near-fatal collapses of premature babies successful its neonatal unit.

Doctors were baffled - the deaths defied mentation and fears were mounting that thing sinister could beryllium astatine play.

The events that followed culminated successful 1 of Britain's darkest transgression trials and the conviction of Lucy Letby, the country's astir prolific kid slayer successful modern times.

"The overwhelming value of grounds leads america to cognize she is simply a slayer and, utilizing her words, she is evil," said elder investigating serviceman Det Supt Paul Hughes.

Shortly aft the missive arrived, Det Supt Hughes met 3 elder medics astatine the infirmary to sermon their mounting concerns.

"What they explained to maine were 2 words - unexplained and unexpected," helium said.

"It was those 2 words the doctors had been trying to enactment out."

Operation Hummingbird was launched and Letby was archetypal arrested astatine her location successful Chester successful July 2018.

At its height, the probe progressive astir 70 officers and civilian staff, with detectives gathering immoderate 32,000 pages of grounds and sifting done reams of aesculapian records and data.

Ahead of Letby's proceedings successful October, astir 2,000 radical were spoken to and astir 250 radical were identified arsenic imaginable witnesses.

Time and again, the grounds each led to the softly spoken young caregiver from Hereford who was often recovered moving overtime arsenic she made aboriginal strides successful her career.

"Nice Lucy", arsenic 1 doc called her.

Letby was interviewed for astir 30 hours implicit the people of her 3 arrests successful 2018, 2019 and 2020.

While Det Supt Hughes recovered her to beryllium "co-operative", helium recalled however she failed to amusement immoderate overt signs of either empathy oregon sympathy. Her answers were often clinical.

"She's a hard 1 to enactment retired due to the fact that she is emotionless," helium said. "She doesn't respond [in a way] I would person expected.

"For example, we didn't spot immoderate sadness oregon immoderate passionateness oregon thing much similar an guiltless idiosyncratic banging connected the array demanding that we should spell and find the due killer."

This was the aforesaid for Det Ch Insp Nicola Evans, who recovered Letby to beryllium "nothing retired of the ordinary", describing her arsenic "calm and quiet".

"Lucy Letby, for me, is 'beige' successful that she was a mean pistillate successful her 20s with a mean life," she said.

"She had a societal life, a ellipse of friends, a family, and she was embarking connected her career. She utilized that normality to signifier spot and past abused that trust.

"There was intelligibly thing precise deceptive astir that. That normality gave her a screen to perpetrate the crimes she did."

As the nett closed astir Letby, 1 happening remained unclear - wherefore would a caregiver who had dedicated her vocation to caring for the sickest of babies present privation to termination them?

"I don't deliberation we cognize wherefore Lucy Letby did this and we whitethorn ne'er cognize wherefore and that's truly difficult," said Det Ch Insp Evans.

"I can't ideate however a genitor indispensable consciousness accepting that."

In the autumn of 2017, Pascale Jones from the Crown Prosecution Service archetypal became progressive successful the case.

She believes Letby was capable to get distant with her appalling crimes by varying the subtle ways successful which she harmed babies successful her care.

"If she'd stuck to 1 modus operandi, she would person astir apt been recovered retired sooner," she said.

"But due to the fact that she diversified the ways successful which she was attacking babies she was preying connected their vulnerabilities.

"And she was ever acceptable to rationalise [and say] 'look, this tin beryllium explained'."

This is simply a distressing lawsuit truthful if you, oregon idiosyncratic you know, request assistance aft speechmaking astir it, the details of organisations offering assistance tin beryllium recovered connected the BBC Action Line website.

While Letby's precise motives person ne'er been explained, that was not needfully a occupation for prosecutors.

"What we've got to beryllium is the transgression intent and the ways successful which she was inflicting this harm was intelligibly lethal," Mrs Jones said.

"She was turning innocuous substances into lethal weapons."

Almost 4 years later, Mrs Jones said she present believed Letby was "all astir control".

"I've seldom travel crossed a property who is arsenic self-centred arsenic she was. All astir herself.

"The powerfulness she was granting herself of beingness and decease implicit the babies astatine her mercy.

"Mercy? She didn't amusement any."

Letby was was convicted connected Friday of murdering 7 babies and attempting to termination six others.

Jurors spent much than 110 hours weighing up 9 months of often harrowing evidence.

While she awaits her sentencing proceeding connected Monday, Operation Hummingbird remains progressive with the unit precocious recruiting much detectives to articulation the team.

"I'm definite the nationalist would expect america to look astatine the full footprint of Lucy Letby's career," said Det Supt Hughes.

This includes admissions connected to the neonatal portion astatine the Liverpool Women's Hospital portion Letby was connected placement there.

The families of babies who are a portion of this probe person been informed.

"From 2012 done to 2016, determination were much than 4,000 admissions of babies into the neonatal units of some hospitals for america to enactment through," said Det Supt Hughes.

"This does not mean we are investigating each 4,000.

"It conscionable means that we are committed to a thorough reappraisal of each admittance from a aesculapian perspective, to guarantee that thing is missed passim the entirety of her employment arsenic a nurse.

"Only those cases highlighted arsenic concerning medically volition beryllium investigated further.

"We privation to beryllium assured that erstwhile we get to the extremity of Operation Hummingbird and accidental we person identified each offence if determination are more."