Banezir Bhutto got killed by the lobby who had guaranteed her cooperation to Musharaf. That included people from United States and also form Pakistan. This is a underworld who had to keep its credibility make BB a lesson for the others who dare disagree with their commitments.
She got killed and her murders will never be caught.. just like Murderers of Zia-Ul-Haq never got spotted. Forget Murder of BB, no matter who comes to the power, no one will investigate and bright culprits to justice. This is how the world-rules. Welcome to 20th Century.