Detectives have been granted more time to question a nurse on suspicion of murder as they revealed two more deaths of patients at a hospital linked to allegations of sabotage.
Rebecca Leighton, 27, was arrested on Wednesday morning at her home a mile away from her workplace at Stepping Hill Hospital in Stockport, which is at the centre of the inquiry into the tampering of medication.
The latest fatalities to be linked to the contamination of saline solution with insulin are Alfred Derek Weaver, 83, and an 84-year-old woman.
Mr Weaver, known as Derek, died on Thursday after suffering a hypoglycaemic episode on July 11.
In a statement, his brother Graham and sisters Lynda and Margaret said: "He loved dining out at French restaurants and had a keen interest in cars and classical music. He was a lovely gentleman who will be deeply missed."
Tracey Arden, 44, George Keep, 84, and Arnold Lancaster, 71, are thought to have died following the alleged deliberate contamination of saline solution with insulin.
Speaking about the latest case of the 84-year-old woman, Greater Manchester Police Assistant Chief Constable Ian Hopkins said: "This was referred to us by the coroner and after a review of the circumstances surrounding this death - notably the low blood sugar level - we have decided to investigate further."
Mr Hopkins added: "I want to make it abundantly clear that we are working closely with the coroner and, as is to be expected, it is likely we will be asked to investigate further deaths."
In a statement, Greater Manchester Police said: "Police have been given more time to question a woman arrested on suspicion of murder.
"A warrant of further detention has been granted and is due to expire at 9.05pm on Friday.