{¶ 1} This is an appeal from a judgment dismissing a complaint for a writ of prohibition to prevent a single judge from deciding a postconviction-relief petition *307when the relator was sentenced to death by a three-judge panel. Because this claim is not cognizable in an extraordinary-writ action, we affirm.

{¶ 2} A grand jury indicted appellant, Donald Ketterer, for aggravated murder with three death specifications, as well as for aggravated robbery, aggravated burglary, grand theft of a motor vehicle, and burglary. Ketterer waived his right to a jury trial and pleaded guilty to the charges before a three-judge panel. Appellee, Butler County Common Pleas Court Judge Patricia S. Oney, was one of the three judges. After receiving the evidence presented, the panel found Ketterer guilty as charged.

{¶ 3} Following a penalty-phase hearing, the three-judge panel sentenced Ketterer to death on the aggravated-murder charge and to prison terms and fines for the remaining felonies. On appeal, we affirmed the judgment, including the death sentence. State v. Ketterer, 111 Ohio St.3d 70, 2006-Ohio-5283, 855 N.E.2d 48.

{¶ 4} In December 2004, Ketterer filed a petition for postconviction relief in the trial court. In April 2005, Ketterer filed a motion to reconvene the three-judge panel that sentenced him to death, for the purpose of ruling on his petition. In April 2006, Judge Oney denied Ketterer’s motion.

{¶ 5} Ketterer subsequently filed a complaint in the Court of Appeals for Butler County for a writ of prohibition to prevent Judge Oney from ruling on his petition for postconviction relief. Ketterer claimed that R.C. 2945.06 vests the three-judge panel that sentenced him to death with exclusive jurisdiction over the petition. In October 2006, the court of appeals granted Judge Oney’s motion to dismiss Ketterer’s prohibition complaint.

{¶ 6} We affirm the judgment of the court of appeals. “An alleged violation of R.C. 2945.06 is not cognizable in an extraordinary writ action and may be remedied only in a direct appeal from a criminal conviction.” Kirklin v. Enlow (2000), 89 Ohio St.3d 455, 732 N.E.2d 982 (affirming dismissal of prohibition complaint); see, also, cases cited in Kirklin at 455-456, 732 N.E.2d 982. “The failure of a court to convene a three-judge panel, as required by R.C. 2945.06, does not constitute a lack of subject-matter jurisdiction that renders the trial court’s judgment void ab initio and subject to collateral attack” by extraordinary writ. Pratts v. Hurley, 102 Ohio St.3d 81, 2004-Ohio-1980, 806 N.E.2d 992, syllabus; see, also, In re J.J., 111 Ohio St.3d 205, 2006-Ohio-5484, 855 N.E.2d 851, ¶ 12. Ketterer, has an adequate remedy by way of appeal from a ruling by Judge Oney on his petition for postconviction relief.

Judgment affirmed.