A Taliban/alquida insurgent was killed in 2011 by RM commandos.

7 have been arrested for murder.
Another marine involved( possibly the 8th man in the section ) reported the incident recently.
Probably a disgruntled former marine with an axe to grind.

He probably turned on his collegues because they gave him a hard time.
Jack bastards, Jonah's and barrack lawyers usually leave feeling disgruntled, it's their selfish nature, they blame others for their faults, hence this idiotic case!