How to Secure a house after winning an auction

[Edgar N.]

I'm working with a friend on a real estate deal. 
We recently bought a house at auction, and it looked great. We planned to fix and flip. The property is 1 hour from where we live, so we happily waited for the contract to be ratified. We rechecked it two weeks after winning the contract, and almost everything was gone. Cabinets, outlets, AC, heater, doors. The whole place was cleared out. 

We're obligated to continue with the purchase now and find waaay more money for repairs than anticipated.

How do you prevent previous owners from emptying a house before a contract is ratified?
Any suggestions on how to proceed from here?