A nurse at Stockport's Stepping Hill Hospital has been found guilty of murdering and poisoning patients.
Victorino Chua, 49, injected insulin into saline bags and ampoules while working on two wards at Stepping Hill Hospital in Stockport in June and July 2011.
These were then unwittingly used by other nurses on the ward - leading to a series of insulin overdoses to mainly elderly victims.
Chua was convicted of murdering two patients - Tracey Arden and Derek Weaver - but cleared of a third murder by the jury at Manchester Crown Court, which had been deliberating for 11 days.
The Crown said the Filipino father-of-two had decided to take out his personal frustrations on patients "for reasons truly known only to himself".
After police were called in, Chua was said to have "changed tack" by sabotaging prescription charts, doubling and trebling dosages - some with potentially lethal consequences - leading to his arrest in January 2012.
Among the evidence produced by the prosecution was a self-penned letter found at Chua's home in Stockport after his arrest.
In the letter, described as "the bitter nurse confession" by Chua, the he said he was "an angel turned into an evil person" and "there's a devil in me", who had things he would "take to the grave".
In a statement released after the verdicts, Stepping Hill Hospital described their former nurse as an "extremely dangerous criminal".
The Hospital also confirmed new security measures in place around the storage of saline and management of prescription charts.