Three bosses at the hospital where Lucy Letby worked have been arrested on suspicion of gross negligence manslaughter, police have said.
The three, who have not been named, were arrested on Monday as part of the investigation into the actions of leaders at the Countess of Chester hospital (CoCH).
Letby, 35, is serving 15 whole-life prison terms after being convicted of murdering seven babies and attempting to murder seven others in the year to June 2016.
The former neonatal nurse is seeking to overturn her convictions at the Criminal Cases Review Commission (CCRC), having lost two legal challenges at the court of appeal.
Det Supt Paul Hughes of Cheshire constabulary said on Tuesday: “In October 2023 following the lengthy trial and subsequent conviction of Lucy Letby, Cheshire constabulary launched an investigation into corporate manslaughter at the Countess of Chester hospital.
“This focuses on senior leadership and their decision-making to determine whether any criminality has taken place concerning the response to the increased levels of fatalities.
“In March 2025 the scope of the investigation widened to also include gross negligence manslaughter.
“This is a separate offence to corporate manslaughter and focuses on the grossly negligent action or inaction of individuals.
“It is important to note that this does not impact on the convictions of Lucy Letby for multiple offences of murder and attempted murder.”
He added: “As part of our ongoing inquiries, on Monday 30 June three individuals who were part of the senior leadership team at the CoCH in 2015-16, were arrested on suspicion of gross negligence manslaughter.
“All three have subsequently been bailed pending further inquiries.”
The arrests are the first in the case since Letby was originally arrested in July 2018. The university graduate, originally from Hereford, has been in custody since November 2020.
Police have faced mounting questions about Letby’s convictions after an international panel of experts announced in February that they had found no evidence of criminality against her after reviewing medical records and other documents.
Mark McDonald, the barrister now representing Letby, handed two large dossiers of new expert reviews to the CCRC earlier this year.
But on Tuesday Cheshire constabulary said its criminal investigation into the former nurse, hospital bosses and the hospital itself would continue.
Hughes said: “Both the corporate manslaughter and gross negligence manslaughter elements of the investigation are continuing and there are no set timescales for these.
“Our investigation into the deaths and non-fatal collapses of babies at the neo-natal units of both the Countess of Chester hospital and the Liverpool women’s hospital between the period of 2012 to 2016 is also ongoing.”