General Antonio Taguba, who investigated Abu Ghraib.
Seymour Hersh's story on General T.
The guy knew the trail at AG went above Gen. Karpinsky, and was ordered not to follow the trail. The list of people who can give a major general orders is rather small.
Lieutenant Generals.
Full Generals.
SecDef.
VPOTUS.
POTUS.
Then, after he "completed" his investigation, he was put out to pasture and forced into retirement. For being a straight shooter and doing his job competently.
I think if we are going to investigate torture, putting General Taguba on the stand is a good place to start. I'd like to know who ordered him not to follow leads.