A nurse arrested on suspicion of murdering eight babies at a UK hospital has been released on bail.

Detectives in Cheshire questioned Lucy Letby for three days before she was released on Friday morning. The 28-year-old was arrested on Tuesday as part of a year-long investigation into the deaths of babies at the Countess of Chester hospital’s neonatal unit in 2015-16.

Letby was held on suspicion of the murder of eight babies and the attempted murder of six others. She has not been charged. Police said she had been bailed pending further inquiries.

“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. Parents of all the babies continue to be kept fully updated and are being supported throughout the process by specially trained officers,” Cheshire police said.

“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.”

The force said the investigation was ongoing and there were no set timescales for progress.

A spokesman for the Countess of Chester hospital NHS foundation trust said: “We are continuing to support Cheshire police with their ongoing investigation.

“In line with the trust’s current policies, the member of staff involved will not be returning to work while this matter is ongoing. We will not be commenting further at this time.”

Letby, who had worked at the hospital for seven years and had been training to work with babies in intensive care, was detained as part of an investigation into 17 deaths and 15 non-fatal collapses of babies between March 2015 and July 2016.

It is understood she was suspended 12 months ago and before this she had been removed from clinical duties and placed in an administrative role.

After her arrest the investigation was widened to include Liverpool women’s hospital, where Letby did some training. Liverpool women’s NHS trust confirmed it was cooperating with the inquiry.

On Friday, police continued to search Letby’s semi-detached home in Blacon. Neighbours said a silver Suzuki car with an NHS parking permit in the windscreen was moved at 4.30am. The vehicle had been moved to a neighbouring driveway on Tuesday to clear space to erect a blue forensics tent, which remains in place.

In the afternoon officers wearing white suits and blue gloves were seen carrying pieces of wood out of the property and digging up the back garden. Forensic teams were also seen conducting a fingertip search of the property, focusing on drains, window ledges and the front garden and garage.

A police presence remained at Letby’s parents’ home in Hereford. A woman who answered the phone confirmed she was Letby’s mother, Susan, 58, and refused to comment about her daughter’s whereabouts.