I agree that a thorough investigation is needed. I am not jumping to any obvious conclusions, but there should be no doubt that the shootings took place and that there are significant civilian casualties. What prompted the shooting needs to be investigated and explained.
Likewise with the Koran burnings. I have seen referenced elsewhere that the personnel who burned them did consult about the proper procedure and were informed, correctly, that burning was the prescribed solution, yet none of "our" spokesmen seem willing to make that case.
My personal opinion is that the Obama administration sanctioned the original leak of the story as part of a plan to stoke and inflame violence against our troops as justification for a planned, humiliating, Vietnam-style withdrawal of our forces before the end of the year.