Tex. Government Code § 22.221

(a) Each court of appeals or a justice of a court of appeals may issue a writ of mandamus and all other writs necessary to enforce the jurisdiction of the court.

(b) Subject to Subsection (c-1), each court of appeals for a court of appeals district may issue all writs of mandamus, agreeable to the principles of law regulating those writs, against a judge of a district, statutory county, statutory probate county, or county court in the court of appeals district.

(c) Each court of appeals for a court of appeals district, other than the Court of Appeals for the Fifteenth Court of Appeals District, may issue all writs of mandamus, agreeable to the principles of law regulating those writs, against:

(1) a judge of a district court who is acting as a magistrate at a court of inquiry under Chapter 52, Code of Criminal Procedure, in the court of appeals district; or

(2) an associate judge of a district or county court appointed by a judge under Chapter 201, Family Code, in the court of appeals district for the judge who appointed the associate judge.

(c-1) The original jurisdiction of the Court of Appeals for the Fifteenth Court of Appeals District to issue writs is limited to writs arising out of matters over which the court has exclusive intermediate appellate jurisdiction under Section 22.220(d).

(d) Concurrently with the supreme court, the court of appeals of a court of appeals district in which a person is restrained in his liberty, or a justice of the court of appeals, may issue a writ of habeas corpus when it appears that the restraint of liberty is by virtue of an order, process, or commitment issued by a court or judge because of the violation of an order, judgment, or decree previously made, rendered, or entered by the court or judge in a civil case. Pending the hearing of an application for a writ of habeas corpus, the court of appeals or a justice of the court of appeals may admit to bail a person to whom the writ of habeas corpus may be granted.