Wouldn't that be termed "witholding evidence"?
Is there ANY part of this investigation that the rellies didn't have a hand in or have some control of? So what, if there was potential embarrassment for them in Sheila's diaries, it wasn't about THEM, it was about truth, something which appears to have been thrown into a cesspit and forgotten!!!!!!............and breeeeeeeeeth! Sorry folks, rant over, better now.