A nurse arrested on suspicion of the deliberate contamination of products and tampering with medical records has had his bail extended.
Filipino nurse Victorino Chua, 47, was held last year following an investigation into the deliberate contamination of saline bags with insulin at Stepping Hill Hospital, which is part of Stockport NHS Foundation Trust.
Mr Chua was arrested in connection with the deaths of three patients, the deliberate poisoning of 19 other patients and the tampering of medical records.
He has had his bail extended until November 29, a Greater Manchester Police spokesman said.
Assistant chief constable Steve Heywood said: “A comprehensive file of evidence continues to be compiled and is currently being reviewed by the Crown Prosecution Service.
“Given the size and scope of the investigation the content being considered is vast and complex and it is only right that it is reviewed meticulously and properly considered before any decision about potential charges is made.
“This process is ongoing and that is why this man’s bail has been further extended, so that a fair and just decision can be reached based upon all the available evidence.”
Police are investigating the contamination of various products with insulin between June 1 and July 15, 2011.
Officers are also investigating the tampering of medical records at the hospital in January 2012.
Mr Chua was questioned last year and then bailed until January this year when his bail was extended July 8.
Twenty-two people were poisoned by the contaminated products, eight of whom have since died - some many months later which were believed to be from natural causes.
They are Tracey Arden, 44, Arnold Lancaster, 71, Derek Weaver, 83, William Dickson, 82, Linda McDonagh, 60, John Beeley, 73, Beryl Hope, 70, and Mary Cartwright, 89.
Staff at Stepping Hill Hospital raised the alarm after noticing “unexplained” low blood sugar levels in patients.
Police later found a number of saline drips had been deliberately contaminated.
Detectives are reviewing and analysing the hundreds of interactions those patients had with a member of staff or visitors during their time at Stepping Hill.
More than 650 statements have been taken and 800 members of staff spoken to.
The tampering affected patients on wards A1, A2 and A3 - acute care wards of seriously ill patients.
Another nurse, Rebecca Leighton, 28, from Heaviley, Stockport, spent six weeks in jail after being held over allegations that she tampered with the saline bags at Stepping Hill.
She was 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 hospital bosses.
She is now suing Greater Manchester Police after officers allegedly gave the public access to her private Facebook account and leaked her name to the media.
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