Sgt Wuterich, Capt McConnell, Lt Col Chessani and the Marine Corps agree that they did kill them. The folks from Kilo Co say that it was a mistake.
"paying $$ to dead civilians families does not implicate crime"
In this case it means the action taken was a mistake.
Emad Jawad Hamza, led an angry delegation of elders up to the Marine camp beside a dam on the Euphrates River. Hamza says, "The captain admitted that his men had made a mistake. He said that his men thought there were terrorists near the houses, and he didn't give any other reason."
That's some guy named Hamza talking, not the Captain.