IMO, at the time(s) BD spoke with LE his main concern was for himself. BD IMO wanted to distance himself as far as he could from being involved in the TB investigation. BD has admitted that he wasn't forthcoming initially with LE and then once he had advice from a lawyer he told them more. I think now today, almost 3 years later, BD may not want to admit to knowing certain things at the time that he did not divulge to LE, IMO.
BD may think that if it all comes out now, his withholding of information back then may put him in a bad light today, IMO. He is now in school and apparently clean and sober, and he's likely told his parents and friends his version of events, as well as LE, so he's going to stick to the story and resist any attempt to recall details that Dungey now puts forward if these versions don't match up. Yup!
All MOO.