A 46-year-old male nurse suspected of murdering three hospital patients at Stepping Hill Hospital has been released on police bail.

Victorino Chua was arrested on Thursday on suspicion of tampering with medical records at the hospital in Stockport, Manchester, and was further arrested on Saturday on suspicion of three counts of murder and 18 counts of causing grievous bodily harm.

He was bailed last night in relation to all matters until an unconfirmed date in April pending further inquiries, Greater Manchester Police said.

Detectives are probing the poisoning of patients at the hospital last summer.

Assistant chief constable Terry Sweeney said: “The public perception is that, in most cases, once a person is arrested they are subsequently charged.

“The reality is very different and it is not unusual for someone arrested for an offence - whatever that might be - to be bailed in order for officers to carry out further inquiries.

“I want to reiterate what we have said from the outset: that this is an extremely complex investigation that requires very detailed forensic and medical analysis.

“These inquiries must be done thoroughly, carefully and with integrity and cannot be rushed.

“It is also important to reiterate that we are continuing to follow the evidence in our search for the truth and cannot rule out making more arrests further down the line.

“This man has been bailed in order for us to continue with our work and it is vital that the public, and in particular the media, do not jump to conclusions or second guess what the outcome of this man’s arrest or our wider investigation will be.

“I know the victims and their families as well as hospital staff and residents want answers.

“I am acutely aware of this and determined to provide these answers but ask for patience while we continue this investigation.”

Detectives had already been given extra time to question Mr Chua and yesterday obtained another warrant of further detention that was due to expire at 10.10am today.

The suspect was being questioned over the contamination of saline drips in June and July last year, causing patients’ blood sugar to fall in “hypoglycaemic episodes”.

Tracey Arden, Arnold Lancaster and Derek Weaver died shortly after experiencing such episodes.

All the deaths took place on wards A1, A2 or A3 - acute care wards caring for seriously ill patients.

Officers investigating the deaths are also looking into a fourth death.

Police are looking into whether the alleged poisoning of William Dickson, 82, suffered at the hospital during the summer was a factor in his death.

The former journalist, of Cheadle Hulme, Cheshire, died on New Year’s Eve.

Mr Sweeney has previously stressed that police have not established the degree to which deliberate contamination of products may have contributed to the four patients’ death.

Police said 21 patients were believed to have been deliberately poisoned.

The cases of a further 21 patients who suffered hypoglycaemic episodes are not being treated as suspicious.

Mr Chua was one of 650 people already spoken to by officers during the complex and long-running investigation at the hospital since the saline drip contamination was discovered.