The saline serial killer may have murdered two more hospital patients, it has emerged.

Police are now investigating the deaths of Derek Weaver, 83, who died yesterday after his blood sugar level plummeted, and an unnamed 84-year-old woman who died on July 14, bringing the death toll up to five.

Other potential victims include Arnold Lancaster, 71, who died on July 11, George Keep, 84, who died on July 14 and Tracey Arden, 44, who died on July 7.

Nurse Rebecca Leighton, 27, is being questioned by police on suspicion of spiking saline solutions at Stepping Hill Hospital in Stockport, Greater Manchester.

 Police believe that as many as 14 patients were given contaminated saline – a salt and water mix – with insulin, which can cause dangerously low blood sugar levels.

Assistant Chief Constable Ian Hopkins, who is working on the case, told The Sun: "As with the deaths of George Keep, Arnold Lancaster and Tracey Arden, the cause of this man and woman's death is not known and it is important we do not lose sight of this fact."

He added: "In relation to the death of the woman, 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.

"The man suffered a hypoglycaemic episode during a timeframe we are looking at."

Anyone with information should call the police incident room on 0161 856 2480.

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