The sergeant who shot the Afghan was in charge of the patrol and he allowed the marine who filmed the incident to be wearing his own headcam against official orders. They knew the rules of engagement, why didn't they just leave the Afghan there, he would probably have died anyway? Then they didn't delete the footage properly. Guilty of three counts of complete stupidity. 

As he said, proudly....... 'I've just broken the Geneva Convention'.

He's a war criminal, that's pretty clear cut to me.

The killing of pows has always gone on in all wars to disagree with this statement is naivety in the extreme.
However as this incident was filmed i think this soldier in question has got off rather lightly with a 10 year sentence.