They exist in secrecy. They operate in secrecy.

From Bill Moyers' Journal (that Wellington referred to in his comments on "We've shot an amazing number of people" below)

BILL MOYERS: That nighttime incident in February that I referred to, you know, one woman killed was a pregnant mother of 10 children. Another was a pregnant mother of 6 children. And our people peddled the story at the time that they had been stabbed to death by family members on an otherwise festive occasion. Was that a lie, do you think, a deliberate lie?

ANDREW BACEVICH: Based on the reports that we read in "The New York Times," yes, it was a deliberate lie. I mean, I think one of the hidden issues here, and it's one that really needs to be brought to the surface, is we have two kinds of forces operating in Afghanistan. We have conventional forces.

BILL MOYERS: The Marines and infantry.

ANDREW BACEVICH: Right. And they are accompanied by reporters. We get at least some amount of information about what these forces are doing and how they're doing it. But in a sense, we have a second army. And the second army are the units that comprise Special Operations forces. They exist in secrecy. They operate in secrecy. Clearly there was a violation of some kind in that incident in February that killed the pregnant women.