A world-renowned hacker, who died in San Francisco in July, overdosed on a mix of heroin, cocaine and other drugs, a coroner's report shows.
New Zealand-born Barnaby Jack was found dead in his bed a week before he was scheduled to give a talk at an event.
An autopsy revealed that "acute mixed drug intoxication" led to his death, San Francisco's medical examiner said.
Mr Jack rose to fame after a 2010 demonstration, in which he hacked a cash machine, making it give out money.
The technique was dubbed "Jackpotting".
He had also emerged as a leading expert in the weaknesses that could be found in medical technology.
'No visible trauma'
In July, the medical examiner had provided no further details into what may have caused the hacker's sudden death.
But the autopsy report has now been made available and says Mr Jack had shown "no visible or palpable evidence of trauma".
Instead, his physical symptoms indicated an accidental overdose of heroin, cocaine, and prescription drugs.
The report said Mr Jack's girlfriend had found him lying in bed unresponsive, with "multiple bottles of beer and champagne in the garbage can".
Mr Jack's death occurred shortly before he was due to demonstrate how heart implants could be hacked at the Black Hat security conference in Las Vegas.
He had said one technique could kill a man from 30 feet (nine metres) away.
Last year, he told the BBC about how he had discovered flaws in widely-used insulin pumps which allowed him to compromise the devices.
The hack made it possible to control them and administer a fatal level of insulin, Mr Jack said.
"My purpose was not to allow anyone to be harmed by this because it is not easy to reproduce," he told the BBC during an interview in April 2012.
"But hopefully it will promote some change in these companies and get some meaningful security in these devices."
Mr Jack's expertise and vivid demonstrations of his knowledge at events like Black Hat earned him the respect of many security professionals.