Premiere Asset Services

I am a first time potential buyer of a property i want to re-hab. I put a bid on the property that had sat vacant for 1 1/2 years. According to the realtor they wanted to unload it. Out of no where came this "phantom" bidder. We received a letter from Premiere Asset Services stating I needed to sign a "Multi Offer Disclosure" Is this a scam? Has anyone had any dealings with them? I think they are trying to jack up the price by having multi-bidders, but being my forst re-hab house I am lost. Any answers are welcom! Thanks