Ethics problem ... What to Do?

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I had an offer in on an REO property. A few days later, I was informed there were multiple offers and the final date to put a final offer in would be 9/24.

Turns out my offer wasnt the highest. However, my agent and I found out a couple days ago that the highest offer was presented by the seller agent's husband (who was a realtor acting on behalf of another client). And, that offer was presented to the bank several days after the final offer date at a value <1% more than my offer was for.

My agent an I are going to file an ethics complaint against both agents, but is there any way to stop the [unethical] sale to the buyer that is currently under contract?