Tax Trust Sales in Texas

[Daniel B.]

I am looking at investing in Tax Trust properties in Texas.  These properties are defined as -"Tax Trust Property is property that did not sell at a Constable’s Sale ordered by Court with Judgment to foreclose the tax lien. Plaintiff Party (taxing unit that filed suit) receives property to hold on behalf of itself and other taxing units. This is referred to as “bid-off” and “struck-off” and is listed in entity’s name with “TAX TRUST”."

If I am looking at buying these properties what are some the things that I need to factor in before I bid on these properties? Title reports?? How do I find out about other liens? Any help will be greatly appreciated!!