No Need to Prove: Damages

Hey ya'll.

I need some advice.

Recently, the moderator of a innerweb chat forum made this statement:

Long as it doesn't involve something that jeopardizes the uptime of the board (idk - threats, RL information, libel, etc etc type of stuff that involves me as a host having to deal with nonsense)

One of these things is being allowed to happen at these boards repeatedly in concern to me myself, and in fact, repeatedly in the thread that quote was taken from. I would PM the guy and ask him to remove the content in the less formal alternative that I have to take, but I am banned from his forum and cannot PM him.

The publisher of another site, along with his own moderator, no longer wished to commit libel on the site this started up on (as if that will stop the damage he has already done, look up "libel per se"), so he is doing it on this other site presumably to let someone else publish the information and bear the responsibility.

Now here is the deal. I can't contact the admin and I can't even use the forums search function to locate the damaging statements... so short of taking appropriate steps with a friendly notification and take down request, I am left with little choice but to take the steps allowed to me under the current law in states and Territories within the United States or its jurisdiction.

Does anyone have a suggestion on how to inform the moderator of this site as to the libelous statements he is publishing (or allowing to be published by moderators of another site that is currently being scrutinized) and request that he not only removes the libelous statements in that thread, but any and all libelous statements that the 2 rogue mods have made and the moderator in question has allowed to stay published before I have to put everyone through the expense of a formal demand?