Finally a decent answer to the cui bono? question that any intelligent person should ask in these cases. I won't claim it's the only possible one but it makes some sense, what is interesting in itself, and it's signed by a respectable analyst who has been claiming for years that Bin Laden is nothing but a puppet of US intelligence, as I do believe too.
The Canadian author claims that the USA exerts much more control over the dark alleys of Pakistani intelligence agency than the new civilian government (that obviously was not interested at all in such attack but rather in improving the relations with its neighbours) and that the main reason for the attack is to sabotage the Indian-Pakistani diplomatic improvements (divide et impera), promote further internal ethnic tensions in both countries and justify even further the intervention in Afghanistan (already declared primary goal by the new Emperor Barack I) and neighbouring Pakistani tribal areas. He also claims that the FBI, along with British M16 and Israeli Mossad, is manipulating the investigation and that, as happened with the Bali attacks, the true masterminds of the crime will never been found. .