Squatters in Texas after Purchase

[Jake F.]

I'm about to go under contract to purchase a house that I found off a direct mail campaign. The current owner has a sub trustee deed in his name. His father originally sold the house on terms to someone about a decade ago. The father died and the son inherited the estate. The son discovered that the buyer had stopped paying the note as well as the taxes, and the son foreclosed on the property 18 months ago. A title company has verified that the guy I'm negotiating with is the current owner. 

There are people living in the house. I asked the owner about them, and he said he has no idea who they are. They might be the people who originally bought the property from his dad, and they might not be. The guy says he knows absolutely nothing about them. Some quick Googling led me to believe that this wouldn't be much of a problem and that I would be able to get rid of them fairly quickly after purchase. Even if they were on a lease, it seems they would automatically be considered month-to-month after the sale and I could give them 30 days to vacate. 

I met with my RE lawyer today regarding something else and mentioned this deal to him. He had a conniption and told me not to do the deal, claiming it would be a disaster and that it would be really hard to get the squatters out. I'm not sure what recourse they could possibly have, since even if they were the original buyers from the father they seem to have lost any possession rights when they were foreclosed upon. My lawyer couldn't really articulate a defense they might put forth, and would only say that it would be a mess in the courts. He admitted he generally only deals with "clean" RE transactions. Lawyer indicated I would not even be able to treat them as month-to-month and give them a 30 day notice. 

Anybody have any experience with this sort of thing in Texas? My impression is that my lawyer is just being a Negative Nancy. For what it's worth, the property is in Hidalgo County.