A nurse has been found guilty of murdering two patients at a hospital in Greater Manchester by contaminating their saline drips.
Victorino Chua was accused of killing three patients and poisoning at least 18 more by putting insulin in their saline drips at Stepping Hill Hospital in Stockport between June 2011 and January 2012.
Chua, originally from the Philippines, denied the 37 charges against him, including three counts of murder, one count of grievous bodily harm with intent and 23 counts of attempted grievous bodily harm.
Following a trial at Manchester Crown Court, Chua has been found guilty of murdering Tracey Arden, 44 and Derek Weaver, 83, by poisoning their saline drips with insulin.
He was found not guilty of the murder of Arnold Lancaster.
Following his arrest in January 2012, police found a letter at Chua's home in which he described himself as an "angel turned into an evil person" who had done things he would "take to the grave".
Chua was also convicted of 31 charges of poisoning and attempted poisoning involving 22 victims.
Chua's motivation for the murders was due to "reasons truly known only to himself", according to the prosecution.
Det supt Simon Barraclough, of Greater Manchester Police, said: "Hidden in plain sight and using unsuspecting colleagues to carry out his sinister plan, Victorino Chua deliberately poisoned and murdered those who were under his care and those who were at their most vulnerable and most in need of help.
"Chua has demonstrated clear narcissistic and psychopathic tendencies and such indiscriminate poisoning is testament to that. He clearly had no regard for his patients and did not give a second thought as to who would be injured or the devastation this would cause them and their families.
"It is so far from keeping with the ethos of those employed at the hospital or as health professionals generally that it is incredulous to believe someone in that vocation to be capable of such malevolence."
Ann Barnes of Stockport NHS Foundation Trust said: "These were shocking and appalling crimes that took place when the patients should have been receiving nothing but the highest quality care.
"This has been an extremely difficult time for the victims and their families and our thoughts have been with them throughout this time."
She added: "Whilst no hospital's systems and processes can offer a complete guarantee against the actions of a determined criminal, additional measures are now in place which go beyond standard practice.
"What is clear from the evidence is that an extremely dangerous criminal has been brought to justice. In part this was due to staff identifying the problems quickly and also fully assisting the police investigation. We would like to thank our staff for showing great professionalism throughout this time."
Chua is expected to be jailed for life when he is sentenced on 19 May.