Well, it'll at least confirm they were in the plane at the time.
And finding tissue belonging to one or more of the terrorists in the cockpit, smeared all over what remains of the flight controls, where it has no business at all being, would be really suggestive of them having been responsible at that.
Certainly enough so to convince me beyond resonable doubt that they were responisble.
I bet you also believe that O J Simpson is innocent.
Watch it, you'll have the families of those Islamist terrorists tracking you down to behead you for doubting the heroism of their sons.