It could be that during his comedown of the drugs I'm presuming he was on he experienced a bout of psychosis in the form of Paranoia and maybe even overhearing things not said, I have experienced similar in my younger more reckless days, and so flew the scene out of the effects of his comedown and thought he needed to hide etc and eventually succumbed to the elements or fell to his death.
Drugs make people do stupid things and also cause alot of deciet probably why the story is not straight and people appear to be not telling the whole story, not because he's been murdered or anything like that but because they do not want to incriminate themselves about the drugs.
As for Jay according to the bartender he was out of it and he looks it to in the footage. Personally I think he just had too much and when the comedown hit him whack... It was a adrenaline packed psychosis.