This may be so far reaching that Durham/Barr are very likely playing this very close to the vest.

Also we have to remember that just because they broke/bent every rule doesn't mean that it can be proven that they committed a crime. The "we where acting on evidence that we thought was good". "We thought that we had to act to protect the country". Sure the guy that falsified the transcripts isn't getting away, maybe they can lean on him to get further up the chain of command.

Their criminals, not idiots. I'm certain they where trying to cover their tracks.