"Now, al-Qaeda may be to blame, but there are compelling reasons to at least doubt that idea. That some al-Qaeda official might claim it is completely understandable."

It's interesting that you choose the term "al-Qaeda official".

And is it completely understandable, because anyone associated with al-Qaeda would lie about such things?

Perhaps Bowser is aware of a track record of al-Qaeda commonly making these types kinds of claims which turn out to be false? If he is unable to provide such evidence, it doesn't seem very accurate to say it's completely understandable. Though perhaps, completely understandable to a simpleton.

"However, blaming al-Qaeda is extremely helpful to Musharraf and Bush. If the Pakistan army or intelligence services was behind it how could Bush continue to support that dictator? Couldn't."

Doesn't this idea get in the way of it being completely understandable that someone speaking for al-Qaeda would falsely claim responsiblity. Couldn't al-Qaeda say that it was member of Pakistan army or intelligence services who doing things which support our cause? And it possible that al-Qaeda could have operatives inside the Pakistan army or intelligence services. But let us assume you right that this doesn't involve al-Qaeda.
Is it not possible to have rogue elements within the Pakistan army or intelligence services- meaning no connection to al-Qaeda or the Musharraf, Bush, Cheney, and ect conspiracy?
From Musharraf interests it would better [or at least equal] that there was rogue elements blame- rather admitting al-Qaeda has agents in Pakistan army or intelligence services or that al-Qaeda can operate without being prevented and captured by those security forces.
And the problem with Musharraf ordering an hit on Bhutto is the number of people involved could mean keeping this secret is at best very problematically. Disregarding that fact that it is not strongly in his interest to kill her. And of course if she hadn't chose to stick her head out the window she probably wouldn't have died- at least on that day.