What would you do?

Personally, I think that making an accusation like that could open you up to a slander lawsuit. Once you get sued, it doesn't matter who is right or wrong. You will still have to defend yourself, which is a pain. And then what if you lose and you end up with a judgment against you. Don't ever think you'll win a lawsuit because you're telling the truth or God is on your side or whatever. It doesn't work that way. IMO, if you think the bidding is crooked, don't bid and walk away. But, again, IMO, you come out blasting on the web, you have to be ready to take the heat. I wouldn't. There's some free legal advice for you. Take it or don't. Good luck.

Chayro +1

I didn't mean to post twice, my mistake. Thank you for the advice. If an admin can delete/move this..

Free legal advice is worth what you pay for it.

Don't entirely agree with Chayro, because truth is an absolute defense to a libel or slander suit, and there are jurisdictional issues - they likely have to sue you in your state and county. It depends on the nature of the "proof" you have, and how you came by it.

Spoken like a true non-lawyer. Truth is a defense you can use after you get sued. The idea is not to get sued in the first place. It's not what you don't know that hurts you - it's what you think you do know. Be careful. It's a dangerous world.