“Whatever it was that darkened the love between the uncle and his niece, their quarrels became more violent and at the end of the summer of 1931 Geli announced that she was returning to Vienna to resume her voice studies. Hitler forbade her to go. The next morning Geli Raubal was found shot dead in her room. The coroner reported that a bullet had gone through her chest below the left shoulder and penetrated the heart; it seemed beyond doubt that the shot was self-inflicted. Yet for years afterward in Munich there was murky gossip that Geli Raubal had been murdered -- by Hitler in a rage, by Himmler to eliminate a situation that had become embarrassing to the party. But no credible evidence ever turned up to substantiate such rumors.”

Source: The Rise and Fall of the Third Reich (1960), pp. 131,132