Who Tried to Kill Benazir Bhutto?

"Benazir Bhutto, twice-elected prime minister of Pakistan and the first woman head of a Muslim state, decided to terminate her self-exile and return to Pakistan last week. By all accounts, more than a million people (mostly poor and young) welcomed her enthusiastically in the port city of Karachi on October 18. In the midst of the celebration, the political rally was targeted by a series of suicide attacks killing around 140 people. Bhutto and her top party leaders, however, remained unhurt.

Who would have been the potential beneficiary of Bhutto's elimination?"