SHE was a billionaire Countess who became one of the most powerful women in horse racing, mixing with royals and holding lavish parties at her Austrian castle. But behind the glamour, Nazi socialite Margit Batthyany hid a murderous dark side that would see her dubbed the' Hostess from Hell'.... But her roaring racing success in the years after the war concealed her previous affairs with Nazi lovers and sick" kill the Jew" parties.... Other sick atrocities were also said to have been carried ou