Thanks for the ping.
...it appears that the CIA undertook the mission with help from American loyalists and retainers within the Pakistani intelligence establishment.
While one wing of the establishment led by PM Shaukat Aziz insists that no terrorists were killed in the bombing, various Pakistani officials, including his own ministers, have confirmed terrorist deaths to the media.
It now transpires that the reason for this confusion is that one wing of the Pakistani establishment has no clue about the underhand working of the other...