A nurse held on suspicion of the murder of eight babies and the attempted murder of another six has been bailed.
Lucy Letby, 28, was arrested on Tuesday after the deaths of 17 infants at the Countess of Chester Hospital between March 2015 and July 2016.
Police are also investigating 15 non-fatal collapses at the hospital’s neonatal unit during that period.
“This is an extremely difficult time for all the families,” Cheshire Police said.
“We continue to 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.”
They added: “Parents of all the babies continue to be kept fully updated and are being supported throughout the process by specially trained officers.”
Officers have been searching Ms Letby’s house in Chester, about a mile from the hospital, and were seen at her parents’ property in Hereford.
Her arrest is part of a long inquiry into a higher than expected number of baby deaths at the hospital.
The cases involve families from Cheshire and north Wales.
Cheshire Police has not officially named the suspect.
Police are said to have arrived at Ms Letby’s home at about 06:00 on Tuesday.
A neighbour said: “I saw lots of police cars arrive, a few cars then a big police van, and gradually more and more came and they put up the tent.”
In a 2013 interview with the Chester and District Standard, Ms Letby said she began working on the unit after graduating and cared for babies requiring various levels of support.
She had worked on the unit as a student nurse during three years of training before qualifying as a children’s nurse at the University of Chester in 2011.
Liverpool Women’s NHS Foundation Trust has confirmed Ms Letby did training placements with them.
A Trust spokesperson said: “We are co-operating with police as part of their investigation, which includes a routine review of patients cared for on our neonatal unit during the time of these placements.
“There is currently no suggestion that any patients at Liverpool Women’s came to any harm in relation to this investigation.”
Police were asked to investigate the deaths of eight babies at Chester in May 2017 – an investigation that has since widened to include nine more.