between this thread and the thread on the autistic Marine is COL John Ewers.

COL Ewers, as the investigater of the Haditha cases and also as adviser to GEN Mattis, is mentioned in the NY Times article as a key figure:

The unlawful command influence ruling determined that a legal adviser for the prosecution should not have had any role in the case. The adviser, Col. John Ewers, had investigated each of the accused Marines and was listed as a prosecution witness.

His presence at meetings with a general overseeing the Haditha cases and prosecutors created an unacceptable perception of unlawful command influence, the military judge concluded.
I'd probably use the term "undue command influence", since "unlawful" gives something of a criminal flavor - especially where there was no finding of actual command influence, but rather "an unacceptable perception" of it.

COL Ewers then went on to become a military judge and ruled against the autistic Marine - see San Diego article:

Fry's attorney, Michael Studenka of Newport Beach, had urged Judge Col. John Ewers not to put Fry on trial.
....
Ewers did not see it that way.

“The defense motion to dismiss for lack of ... jurisdiction was denied,” Lt. Col. Sean Gibson, a Marine spokesman at Camp Pendleton, wrote in a statement to The San Diego Union-Tribune.
What is ironic is lawyer Fidell's statement in the autistic Marine case:

“This strikes me as a stupid case to prosecute,” said Fidell, a senior partner in the law firm Feldesman Tucker Leifer Fidell. “I think the chief of military justice should intervene to have the case dropped.
Might I suggest that, in the Haditha cases, it would have been better if everyone had simply allowed the process to run its course without interference - and the same in the San Siego case.