I find that hard to believe...the marines know the enemy lies all the time. I had heard reports that another US serviceman is invovled in implicating the marines in that case. I hope it's not true...but you sound like you haven't even looked into it at all. Am I wrong?
I have looked into it, and I can't find anything that seems to say they are guilty.
They got one guy to flip by offering him a light punishment. After they had shackled these guys in tehir cells, that seems like an attractive offer. So he tells them what they want to hear.
We need to forget about punishing our troops for doing their jobs and kill the enemy. Get some of our artillery out of there, but send in more Special Forces. Kill al-Sadr and stamp out his army. Drive the terrorists back to their stronghold in the Triangle of Death and then bomb it back to the Stone Age (not a very long trip.)
After we've subdued the enemy and won, then we can worry about punishing our troops for any inappropriate actions if such punishment is merited and then we can make it policy that "when teh Iraqis stand up, we will stand down." But not until then. Until then, we have a war to win. Let's get the job done.