Tex. Loc. Gov't Code § 86.023

If, for collection, a constable receives a bond, bill, note, or account from any person and the constable gives a receipt in an official capacity for the instrument or account, the constable and the constable's sureties are liable under the constable's bond for the amount collected if the constable fails to pay the amount on demand to the person for whom the constable made the collection.