Woman also suspected of attempting to kill six more at Countess of Chester hospital

A healthcare worker is being questioned on suspicion of murdering eight babies and attempting to kill a further six, in the first police investigation into child deaths in hospitals in nearly 30 years.

Cheshire police said the woman was arrested on Tuesday morning and taken into custody. Officers searched a semi-detached house about a mile from the hospital, north-west of the city. It is understood that the address is the home of Lucy Letby, a 28-year-old nurse.

Police launched an investigation in May last year into the deaths of 15 babies and six non-fatal collapses at the women and children’s unit of the Countess of Chester hospital between June 2015 and June 2016. The force said on Tuesday the inquiry had widened to cover the deaths of 17 babies and 15 non-fatal collapses between March 2015 and July 2016.

It is thought to be the most significant police investigation into child deaths in hospitals since the nurse Beverley Allitt, nicknamed the “Angel of Death”, was jailed for 30 years for murdering four children with lethal injections and attempting to murder three more in the early 1990s.

DI Paul Hughes, who is leading the investigation, said: “Whilst this is a significant step forward in our inquiries it is important to remember that the investigation is very much active and ongoing at this stage.

“There are no set timescales for this coming to a conclusion but we remain committed to carrying out a thorough investigation as soon as possible.”

Police said the parents of all the babies involved were being updated and supported by specialist officers.

Hughes said: “We recognise that this investigation has a huge impact on all of the families, staff, and patients at the hospital as well as members of the public. This is an extremely difficult time for all the families and it is important to remember that, at the heart of this, there are a number of bereaved families seeking answers as to what happened to their children.”

Ian Harvey, the hospital’s medical director, said staff were supporting the police.

“Asking the police to look into this was not something we did lightly, but we need to do everything we can to understand what has happened here and get the answers we and the families so desperately want,” he said. “The Countess is now equivalent to a level one special care baby unit and we are confident the unit is safe to continue in its current form.”

Neil Fearn, the chief executive of Pryers Solicitors, the firm representing the families of two babies who died at the hospital, said: “We are hopeful that the investigation can provide answers for the families of these children.

“The death of any child is a tragedy, but this is exacerbated in circumstances where questions remain unanswered. However, we are reassured that the investigation is still ongoing, and that there are further steps to be taken.”

Facebook Twitter Pinterest The Countess of Chester Hospital. Photograph: Anthony Devlin/Getty Images

On a quiet residential street in the Blacon area of Chester, neighbours said they were awoken at around 6am on Tuesday morning when officers surrounded a three-bedroom semi-detached property.

A silver car thought to belong to the healthcare worker was moved to the driveway of an empty house next door. Both homes were cordoned off by police tape and four Cheshire police vehicles were parked at the scene.

On Tuesday afternoon a blue tent stood on the small front garden of the house and officers wearing blue forensic gloves were seen leaving the house with a large brown envelope.

Michael Coupe, a former ambulance technician who has lived on the estate for the past 12 years, said everyone was shocked when they heard that an arrest had been made.

“I came out of the house at around eight and saw them all around the house. With the big blue tent up we initially thought someone had been attacked but then everyone started talking about someone being arrested,” he said. “This is just such a horrible, serious thing that is going on. You never expect something like this to happen on your doorstep.”

Other neighbours said the woman who lived at the address had not been there long and kept herself to herself.

A photograph of Letby in her graduation robes and gown appeared in her local Hereford Times newspaper in December 2011, along with a note from her parents: “We are so proud of you after all your hard work. Love Mum and Dad.”

Plain-clothed police officers were seen searching the house of her parents, Susan, 58 and John, 73, in Herefordshire following her arrest.

A neighbour who did not want to be named said Letby was dedicated to her job. “She is an only child and I believe she got her job as a nurse from her studies at Chester University.”

Another neighbour who wanted to remain anonymous said: “Lucy was just a quiet girl. Nothing strange about her – she was just a normal, lovely girl. The family must be in bits over this.

“We’ve known Lucy since she was about three years old and she was lovely, she always has been. But this is just really shocking.”

Two babies died in the unit in 2013 and three in 2014. There were eight deaths in 2015 and five in 2016.

Last July the hospital stopped providing care for babies born earlier than 32 weeks after the review made 24 recommendations for improvements.

An academic study published in June 2017 found that the death rate among babies at the hospital was at least 10% higher than would be expected at similar types of maternity units elsewhere.

The authors of study – Mothers and Babies: reducing risk through audits and confidential enquires across the UK – looked at stillbirth and neonatal deaths occurring at 165 maternity units around the country in 2015.

They found that the Countess of Chester hospital had the highest neonatal mortality rate of 43 similar-sized hospitals in Britain, with 1.91 deaths per 1,000 births, compared with an average of 1.27 at the other hospitals.

The hospital’s “crude” neonatal death rate – the number of deaths compared with the amount of births – was 2.96 per 1,000 births in that time, according to the study, meaning it was higher than that of all other similar-sized hospitals as well as the national average of 2.5 deaths per 1,000 births.

A report by the Royal College of Paediatrics and Child Health in May said staffing at the hospital’s neonatal unit, which reported a “higher than usual” number of baby deaths, was inadequate.

The review found no definitive explanation for an increase in mortality rates, but identified significant gaps in medical and nursing rotas, poor decision-making and insufficient senior cover.

It also found that deaths in the baby unit had not always been properly investigated within the hospital. All baby deaths should be considered serious incidents and reviewed promptly by a team of experts – a paediatrician, the risk midwife, neonatal nurse and obstetrician. Not all of the babies who died had a postmortem.

The consultants on the unit had not at first noticed any links between the “episodes of collapse” of the babies who died, said the report, “but subsequently they began to notice similarities”, such as mottling on the limbs that appeared after a few minutes of resuscitation. They could find no definite explanation, but this led to downgrading the unit while the experts from the college investigated further.

Prosecutions of healthcare workers are rare and frequently difficult. Anthony Haycroft, a barrister at Serjeants’ Inn Chambers, said proving intent was crucial. In the Countess of Chester case, he said the police “will be looking first of all at the intent and if there was an intention to kill, it is murder. If it is a dangerous act irrespective of any intent, it is gross negligence manslaughter. In both cases, there has to be causation – for the actual death there must be a connection between the medical act and the death.”

Additional reporting: James Gant