Re: LVPD lock
You'll have to provide transcripts and create a convincing trail leading to a forum that has now been taken down, and justify its lack of indexing by any of the major search engines. You'll also have to stick to relatively recent threats, because it can't be very old, or there would be more of a path to follow.
Even with those caveats, it won't be easy. You'll need people willing to testify they saw and read those posts to give them credence. Even then, without an archive, they might be thrown out as hearsay.