Texas Code of Criminal Procedure - CRIM P Art. 15.26. Authority to arrest must be made known

In executing a warrant of arrest, it shall always be made known to the accused under what authority the arrest is made. The warrant shall be executed by the arrest of the defendant. The officer need not have the warrant in his possession at the time of the arrest, provided the warrant was issued under the provisions of this Code, but upon request he shall show the warrant to the defendant as soon as possible. If the officer does not have the warrant in his possession at the time of arrest he shall then inform the defendant of the offense charged and of the fact that a warrant has been issued. The arrest warrant, and any affidavit presented to the magistrate in support of the issuance of the warrant, is public information, and beginning immediately when the warrant is executed the magistrate's clerk shall make a copy of the warrant and the affidavit available for public inspection in the clerk's office during normal business hours. A person may request the clerk to provide copies of the warrant and affidavit on payment of the cost of providing the copies.