I think Courtney Love did it, but whatever.
Theres a whole bunch of shit people can say about it, not just the massive dose of heroin but the last lines of his 'suicide' (retirement?) note, how the shell ended up on the wrong side of his body, the fact that the bitch drugged him before in Europe, the guy who said Courtney offered him money to kill Cobain, etc.

Much of this and the rebuttles can be found at www.justiceforkurt.com
Now I can't say she did it for sure, but there should definately be a trial.