A hospital nurse has been convicted of murdering two of his patients.
Benjamin Geen, 25, was also convicted of causing grievous bodily harm to a further 15 patients at Horton General Hospital in Oxfordshire.
Oxford Crown Court heard the staff nurse from Banbury, injected patients with unauthorised lethal doses of drugs which caused them to stop breathing.
The offences took place between December 2003 and February 2004. Geen had denied all the charges.
Fifteen patients at the Horton General Hospital recovered shortly after they developed breathing difficulties.
However, the trial heard David Onley, 77, from Deddington, died on 21 January, 2004 and Anthony Bateman, 66, from Banbury, died on 6 January, 2004.
Initially, doctors could not explain the abnormally high level of respiratory arrests between December 2003 and February 2004.
Suspicion fell on Geen, a lieutenant in the Territorial Army, when it emerged that the incidents had taken place while he was on duty.
When he was subsequently arrested at the hospital on 9 February, 2004, police found a syringe filled with a potentially lethal muscle relaxant in his pocket.
Robert Robinson - one of Geen's first victims - was admitted to hospital after he drank a bottle of gin and took painkillers.
He stopped breathing when he was given an anaesthetic which he did not need, the court heard.
The 51-year-old said his life had been devastated: "I have no idea what happened when I was in hospital.
"It's hard to describe what the guy did, why he did it, I just don't know, I'm just relieved it's over."
The court heard how Geen looked "elated" as his patients went into respiratory arrest and even "boasted" to one doctor: "There is always a resuscitation when I'm on duty."
He used different methods to send his victims to the point of death including overdoses of insulin and sedatives.
Prosecutor Michael Austin Smith QC told the jury that toying with patients' lives was a price Geen was willing to pay in order to satisfy his perverse needs.
When patient Timothy Stubbs was admitted with stomach pains and later transferred to the intensive care unit, the drugs midazolam, a sedative, and vecuronium, a muscle relaxant, appeared in his urine sample.
The drugs had not been prescribed by the doctors at the hospital.
Mr Smith said: "People were at death's door. Most were lucky - two were not."
Detective Superintendent Andy Taylor, who led the murder investigation, said: "Ben Geen abused this position of trust.
"We may never know what motivated him to select and poison his victims.
"It is clear that he wanted to be the centre of attention and in order to fuel this desire, brought some of his patients to the brink of death and coldly murdered two of them."