Buying properties before they come up for auction

Hi,

I am have been scouring websites for properties that go into foreclosure or pre-foreclosure in Nashville.  I have participated in online bidding as well as gone to the county steps where the auction takes place.  However, I have been seeing a trend that a lot of the hot property deals get sold to a third party or are cancelled (and don't return) before they come up for their auction date.  Can someone give me insight into how this is happening?  I tried to follow one deal down the rabbit trail but didn't get anywhere- trying to find owner's contact info, calling the bank that took possession, reaching out to the trustee of the property...but nothing.  Any ideas or tricks on how to get to these properties before they come up on the auction steps? Thanks!