Last Friday, we reported that legislation has been languishing to make State Department security contractors more accountable. But yesterday, the Washington Post reported that the Justice Department had sent target letters to six Blackwater guards involved in last September’s Nisour Square shooting.

Prosecutors typically issue such letters as a warning they will file charges. The final decision on whether to indict "may not be made until October," the Post reports.

Despite the potential charges, the legal ambiguity for contractors like Blackwater still exists. The Post reports that Blackwater's lawyers, in fact, have already argued to prosecutors that current law doesn't apply to State Department contractors. But prosecutors seem willing to risk convincing a judge, through some display of litigious dexterity, that current law does apply. It would be the first time the question is tested in court.

As legal experts tell the Post, even if prosecutors win that battle, trying to prove that guards operating in a war zone essentially committed murder will be extraordinarily difficult; as one former prosecutor put it, "exponentially tougher" than a bad police shooting case.