Conversation so far:
What does Baitullah Mehsud have to do with Benazir Bhutto's assassination?
On 28 December 2007 the Pakistan government claimed that it had strong evidence regarding Baitullah Mehsud as the man behind the assassination of former Prime Minister Benazir Bhutto.
How was Baitullah Mehsud involved in the assassination of Benazir Bhutto?

Question: Why did he kill him?
Self-contained rewrite: Why did Baitullah Mehsud kill Benazir Bhutto?