Security Deposit withholding not knowing prior condition

[Lauren M.]

We bought a junker of a rental property that we hoped to renovate to improve rental income and equity. The tenants moved out. We do not know the prior condition of the property before the current tenants moved in, but there were broken panes of glass on the windows, piles of hidden trash on the side of the house, etc when they moved out. The tenants could easily say it was previous renters. Since we do not know the state of the property before they moved out, what are we legally allowed to keep to pay for these items? The tenant also asked over text message how much they would be getting back and we stated a number. Since then, we found the crawl space area has a lot of items and junk that we need to dispose of (again, we still wouldn't be able to prove if it was the tenants that just moved out or the tenants before them). Could we change our minds and deduct more money since we found junk that needs to be disposed of?