The deaths of two more patients are now being investigated by detectives at a hospital where it is believed medical equipment was sabotaged.
Greater Manchester Police said yesterday that a total of five people are thought to have died as a result of malicious tampering at Stepping Hill hospital in Stockport.
That number is expected to rise as more suspicious deaths that occurred recently in the two wards at the centre of the inquiry become part of the huge investigation, police said.
One man aged 41 is still fighting for his life while a further eight patients have been made ill amid fears that saline solutions used to rehydrate them were injected with insulin.
Police were granted more time last night to continue questioning staff nurse Rebecca Leighton, 27, who was arrested on Wednesday on suspicion of attempted murder.
The latest suspected victims were both pensioners. The first, an 84-year-old woman, who has not been named, died on 14 July. Her case was referred back to the police yesterday by the coroner after she was found to have been suffering from low blood-sugar level.
The second, Alfred Weaver, 83, underwent a hypoglycaemic episode on 11 July and died yesterday morning. Mr Weaver's brother Graham and sisters Lynda and Margaret, paid tribute to the widower. "Derek was a self-taught electronic engineer and ran a successful alarm business in Stockport. He was a lovely gentleman who will be deeply missed," they said in a statement.
Further pathology tests are being carried out on all five of the suspected victims, including George Keep, 84, Arnold Lancaster, 71, and Tracey Arden, 44. Police have yet to confirm that any of them died as a result of insulin poisoning. All were suffering from other serious ailments.
Sixty detectives are working on the case with teams of officers examining forensic material and medical records. Dozens of members of staff have already been questioned by police while nurses are working in teams of two as they dispense drugs. Visitors to the hospital are greeted by heavy security.
The deaths have sent shockwaves through the community living around the large teaching hospital in Stockport. Assistant Chief Constable Ian Hopkins said anything suspicious would now fall under the remit of the inquiry team. He reassured anxious patients that no suspicious activity had occurred since the police were called in to investigate.
He said: "I want to make it abundantly clear that we are working closely with the coroner and it is likely we will be asked to investigate further deaths. In the main these are likely to be deaths of people who are elderly and/or ill, and we fully support the coroner's 'belt and braces' approach to ensuring future deaths that require further investigation are appropriately investigated and scrutinised."
Officers who searched Ms Leighton's flat a mile from the hospital took away bags of items and computer equipment on Wednesday. Detectives were called in last week after a nurse reported a higher than normal number of patients on her ward with "unexplained" low blood-sugar levels.
Alfred Weaver, 83
Died yesterday after suffering a hypoglycemic episode 10 days earlier. Widower of 20 years, he ran a successful alarm business in Stockport where he had lived since the 1960s. Cause of death still unknown.
George Keep, 84
Was suffering from lung cancer and recovering from a fractured hip but his condition suddenly deteriorated after he was put on a saline drip last week. Died on 14 July. Cause of death still unknown
Arnold Lancaster, 71
Retired photographer with the Stockport Express. Spent time living in Australia and was a model railway enthusiast. Died on 11 July after being admitted to the hospital. Cause of death still unknown.
Tracey Arden, 44
Grandmother and mother of two who was suffering from multiple sclerosis. Died suddenly on 7 July two hours after being placed on a saline drip. Was living in care and was regularly admitted with associated illnesses after being diagnosed with MS 10 years ago. Cause of death still unknown.
Unnamed woman, 84
Died on 14 July but case was referred back to police by a coroner yesterday after discovered to be suffering from low blood sugar levels. Cause of death still unknown.