Davy Jones, the much-loved member of The Monkees, had cannabinoids in his system according to the autopsy for the star which was recently released. As you might surmise from the name, they're a family of drugs that include marijuana. Tmz reports however that there isn't yet clarification as to whether Jones was smoking marijuana at the time of his death but there is absolutely no indication on the report that his passing actually came from the cannabinoids.
What it does say is what many had already reported, that the 66 year-old died of a heart attack, with severe build-up in his arteries. He suffered the attack in February while visiting horses he owned at a Florida ranch, being pronounced death shortly after being rushed to hospital.