Liens: Dad Had a Used Car Lot and is Now Deceased

My question involves vehicle registration or title in the state of: Texas
My dad had a used car lot (tote the note) and passed away in 2012.
I know there are several cars that my dad is still the lien holder on, due to
people still owing money.
How would I go about finding the titles to cars and trucks still in my
dad's name. Is there somewhere that can just pull up my dads name
and locate these titles. I am the independent executor of the estate.
I am dealing with a court case now
that a truck my dad shows to be the lien holder was seized due to drugs
being in the truck. I want the titles out of my dads name.
Any help will be great
Thank you
Debbie

Liens: Dad Had a Used Car Lot and is Now Deceased