I don't know if anyone here is familiar with it, but Tom Grant, a private-investigator hired by Courtney Love after Cobain's death, had found a great deal of contradictory evidence in lieu with Cobain having committed suicide. I don't think Courtney Love could have/would have killed Cobain, because even if she didn't have feelings for the man, she was, quite-frankly, riding his coat-tails to success and stardom. I know the Wikipedia article has a section for the "Suicide Dispute," it's a concise, but otherwise good read.

Kurt Cobain - Wikipedia, the free encyclopedia
ThePeacockNamethTom Reviewed by ThePeacockNamethTom on . Did Courtney Love KILL Kurt Cobain? Justice For Kurt Cobain - Investigation - Eldon Hoke aka El Duce I wouldn't be surprised that money-grubbing whore did it. According to Kurt's friends, he wasn't suicidal in the last several weeks leading to his apparent suicide, but wasn't happy with the marriage to Courtney Love. Apparently when Kurt started making divorce preparations, that's when he killed himself. Mere coincidence? Or Murder? Rating: 5