Detectives investigating the deaths of seven hospital patients who were poisoned with insulin say they are making “good progress”.
It is nearly one year since staff at Stepping Hill Hospital in Stockport, Greater Manchester, raised the alarm after they found contaminated vials of saline and noticed “unexplained” low blood sugar levels in patients.
Police later found the saline drips of 22 people had been deliberately contaminated between June 1 and July 15 last year.
They are reviewing and analysing each of the hundreds of interactions all those patients had with a member of staff or visitor during their time at Stepping Hill.
More than 650 statements have been taken and 800 members of staff have been spoken to.
In addition, almost 3,000 exhibits of potential evidence have been gathered and information has been obtained on more than 2,300 people including patients, staff and visitors.
Experts have conducted a series of specialist medical tests including comprehensive examinations of drugs present in the body before and after death, as well as any signs of natural disease.
The levels of insulin administered have been measured and clinical reviews have taken place of the patients’ general state of health before admission to hospital.
A similar analysis of 20 other patients who suffered hypoglycaemic episodes but who are not believed to be victims of poisoning is also being conducted.
The tampering affected patients on wards A1, A2 or A3 - acute care wards for seriously ill patients.
The deaths of Tracey Arden 44, Arnold Lancaster, 71, and Derek Weaver, 83, are being investigated as murders while those of Bill Dickson, 82, Linda McDonagh, 60, John Beeley, 73, and Beryl Hope, 70, are being treated as cases of grievous bodily harm as tests continue.
A male nurse arrested in connection with poisoning deaths is on bail pending further inquiries.
Filipino-born Victorino Chua, 46, was arrested in January on suspicion of tampering with medical records at the hospital and was further arrested on suspicion of three counts of murder and 18 counts of causing grievous bodily harm.
Another Stepping Hill nurse, Rebecca Leighton, 28, from Heaviley, Stockport, spent six weeks in jail after being held over allegations she had tampered with the saline bags.
She was then released and cleared of any wrongdoing last September when prosecutors said there was not enough evidence against her, but she was subsequently sacked for theft by bosses.