Cassel, J.

I. INTRODUCTION

Jeffrey A. Hessler appeals the order of the district court denying his second action for postconviction relief and a writ of error coram nobis. All of his claims — relating to mental competency, errors or misconduct at trial, and ineffective assistance of counsel — were or could have been litigated on direct appeal or in his first postconviction action. Thus, they were procedurally barred. And his reference to two recent decisions of the U.S. Supreme Court provides no basis to deviate from our procedural rules. Finally, he failed to raise any basis warranting coram nobis relief. We affirm.

II. BACKGROUND

Hessler was convicted of first degree murder, kidnapping, first degree sexual assault on a child, and use of firearm to commit a felony for the sexual assault and killing of 15-year-old Heather Guerrero. He was sentenced to death on the murder conviction and various terms of imprisonment on the other convictions. The circumstances which led to Hessler's convictions and sentences may be found in State v. Hessler.1

We affirmed Hessler's convictions and sentences on direct appeal.2 We summarized the assignments of error raised in his appellate brief, in pertinent part, as follows:

[T]he district court erred in ... (3) failing to excuse for cause potential jurors who had formed opinions regarding Hessler's guilt; (4) overruling his motion to change venue; [and] (7) granting his request to waive counsel and appear pro se at sentencing and failing to make a determination regarding his competency to waive counsel.3

After we affirmed his convictions and sentences, Hessler filed his first action for postconviction relief. In his first postconviction motion, Hessler asserted claims related to ineffective assistance of trial and appellate counsel, errors at trial, and prosecutorial misconduct. He claimed that his trial counsel was ineffective for failing to take various actions regarding his mental competency, juror bias, and venue. And he alleged that his appellate counsel was ineffective for failing to raise and argue those issues. Finally, he asserted that the trial court erred by failing to order a competency evaluation and that the State committed prosecutorial misconduct by failing to suggest such an evaluation.

The district court ordered an evidentiary hearing on the sole issue of whether Hessler's trial counsel was ineffective for failing to raise the issue of competency after Hessler's convictions but prior to the determination of any mitigating factors and sentencing. Before the mitigation portion of the sentencing phase began, Hessler moved the court to proceed pro se. He had been represented by counsel up until that point. The court ultimately rejected Hessler's ineffective assistance claim, finding that the record affirmatively showed that he was competent. It therefore denied postconviction relief. We affirmed the denial of postconviction relief on appeal.4

Hessler then filed the present, second motion for postconviction relief. As noted above, the claims asserted in the present motion related to mental competency, errors or misconduct at trial, and ineffective assistance of counsel. The district court summarized Hessler's 17 claims as follows:

The district court found that Hessler's second postconviction motion failed to raise any ground for relief not previously available to him. It noted that the issues of mental competency and ineffective assistance of trial and appellate counsel were litigated on direct appeal or in his first postconviction action. And his various assertions of errors or misconduct at trial were previously litigated or were known and could have been raised in the prior proceedings. Finally, it observed that no constitutional basis existed for his claim of ineffective assistance of postconviction counsel. It therefore denied postconviction and coram nobis relief and dismissed the motion. Hessler timely appeals.

III. ASSIGNMENTS OF ERROR

We consolidate and restate Hessler's numerous assignments of error. Hessler assigns that the district court erred in failing to grant an evidentiary hearing on each of his 17 claims.

IV. STANDARD OF REVIEW

A defendant requesting postconviction relief must establish the basis for such relief, and the findings of the district court will not be disturbed unless they are clearly erroneous.5 An evidentiary hearing on a motion for postconviction relief must be granted when the motion contains factual allegations which, if proved, constitute an infringement of the movant's rights under the Nebraska or federal Constitution.6 However, if the motion alleges only conclusions of fact or law, or the records and files in the case affirmatively show that the movant is entitled to no relief, no evidentiary hearing is required.7

Whether a claim raised in a postconviction proceeding is procedurally barred is a question of law.8 When reviewing a question of law, an appellate court reaches a conclusion independent of the lower court's ruling.9

V. ANALYSIS

We first dispose of a preliminary issue. Hessler assigned as error the district court's denial of an evidentiary hearing on the claims raised in his second motion for postconviction relief. In his brief, he assigned 17 errors and argued the merits of each of his 17 claims. But he omitted claims 8 and 10 from his assignments of error by duplicating other claims. We recognize our precedent that an appellate court does not consider errors which are argued but not assigned.10 But we do not treat claims 8 and 10 as being waived. The sentences imposed in this case are grave, and the duplications of the other claims make it clear that he intended to assign error to the district court's disposition of each of his claims but committed a typographical error.

1. DENIAL OF POSTCONVICTION RELIEF

This is Hessler's second motion for postconviction relief. A defendant is entitled to bring a second proceeding for postconviction relief only if the grounds relied upon did not exist at the time the first motion was filed.11 The need for finality in the criminal process requires that a defendant bring all claims for relief at the first opportunity.12

We have recognized two circumstances which provide a new ground for relief constituting an exception to the procedural bar in postconviction proceedings. First, if a defendant brings a motion for postconviction relief based on ineffective assistance of trial or direct appeal counsel which could not have been raised earlier, this is a basis for relief that did not exist at the time of the prior proceeding.13 Second, if a defendant brings a successive motion for postconviction relief based on newly discovered evidence that was not available at the time the prior motion was filed, this is a basis for relief that did not exist at the time of the prior proceeding because it was not available to the defendant.14

None of the 17 claims asserted by Hessler raised a new ground for relief constituting an exception to the procedural bar. Thus, the district court correctly denied Hessler's motion. For the sake of brevity, we organize our analysis in accordance with the common themes shared among the 17 claims: mental competency, errors or misconduct at trial, and ineffective assistance of counsel.

(a) Mental Competency

Claims 1, 3, 4, and 10 pertain to Hessler's mental competency during the proceedings against him. Hessler asserted that due to mental illness, he was incompetent to stand trial and unable to waive his right to remain silent, his right to counsel, and his right to be present.

But Hessler challenged his competency to waive the right to counsel on direct appeal.15 He alleged that the trial court erred in granting his request to waive counsel and appear pro se at sentencing and in failing to make a determination regarding his competency to do so.16 We rejected this claim because the trial court had no reason to doubt Hessler's competency to waive counsel.17 Having already litigated this claim, Hessler was procedurally barred from raising it in the present motion. A motion for postconviction relief cannot be used to secure review of issues which were or could have been litigated on direct appeal.18

Hessler's three remaining claims regarding his mental competency were similarly barred. These claims were known and could have been litigated on direct appeal. Consequently, we find no error in the district court's denial of an evidentiary hearing on claims 1, 3, 4, and 10.

(b) Errors or Misconduct at Trial

Claims 2, 5, 13, 15, 16, and 17 relate to errors or misconduct at trial. Briefly, Hessler asserted that his convictions and sentences must be overturned because of a biased jury, comments made by the trial judge and prosecution that diminished the jury's role in sentencing, juror misconduct, prosecutorial misconduct, improperly admitted evidence, and cumulative error.

Hessler asserted that his jury was biased on direct appeal.19 He alleged that the trial court erred in failing to excuse potential jurors who had formed opinions of his guilt and in overruling his motion to change venue because he could not receive a fair trial in Scotts Bluff County, Nebraska.20 As this claim was previously asserted and rejected, Hessler was barred from asserting it again.

Hessler's remaining claims of errors or misconduct at trial were similarly barred. These claims were known to Hessler and could have been raised on direct appeal. But he did not do so. We therefore find no error in the district court's denial of an evidentiary hearing on claims 2, 5, 13, 15, 16, and 17.

(c) Ineffective Assistance of Counsel

Claims 6 through 9, 11, 12, and 14 pertain to ineffective assistance of counsel. Hessler asserted that his trial counsel was ineffective for failing to take various actions regarding competency, juror bias and misconduct, venue, cross-examination of witnesses, jury instructions, evidence, and prosecutorial misconduct. He further alleged that his counsel on direct appeal and in his first postconviction action were ineffective for failing to raise and argue all meritorious issues.

As noted above, a new basis for relief may exist if a defendant brings a motion for postconviction relief based on ineffective assistance of trial or direct appeal counsel which could not have been raised earlier.21 But Hessler was able to assert ineffective assistance of trial and appellate counsel in his first postconviction action and did so.22 He was not entitled to do so again. Consequently, his present claims of ineffective assistance of trial and appellate counsel were procedurally barred.

But Hessler also claimed that he received ineffective assistance of counsel in his first postconviction action. He argued that the ineffectiveness of his first postconviction counsel constituted a new basis for relief and rendered any claims not raised in the prior proceedings unavailable to him until the present action. This argument has no merit. Postconviction relief cannot be obtained on the basis of ineffective assistance of postconviction counsel.23 There is no constitutional guarantee of effective assistance of counsel in a postconviction action and therefore no claim for ineffective assistance of postconviction counsel.24

In his brief, Hessler cites Martinez v. Ryan25 as a basis for deviating from our procedural rules and granting an evidentiary hearing on his 17 claims. In Martinez, the U.S. Supreme Court held that a state procedural default does not bar a federal habeas court from hearing a substantial claim of ineffective assistance at trial if, in the initial-review collateral proceeding, there was no counsel or counsel in that proceeding was ineffective. This holding was initially limited to state procedural systems in which ineffective assistance of trial counsel claims were required to be litigated in the initial-review collateral proceeding.26 But the Court later expanded its holding to include state systems in which ineffective assistance of trial counsel claims were highly unlikely to be given a meaningful opportunity for review on direct appeal.27 We assume, without deciding, that Nebraska's postconviction review procedures fall within the purview of the Court's expanded holding.

Martinez did not recognize a constitutional right to effective assistance of postconviction counsel. Based upon principles of equity, it expanded only the types of cause permitting a federal habeas court to excuse a procedural default in a federal habeas proceeding.28 Nothing in Martinez prevents state courts from enforcing procedural defaults in accordance with state law.

Other state courts have reached similar conclusions regarding the effect of Martinez.29 The Supreme Court of Pennsylvania made several observations worthy of note.30 First, it described the Martinez holding as creating a "federal safety valve to allow for a third level of review — exclusively federal — if the subject claim involved a trial default, and initial collateral review counsel did not recognize it."31 Second, it recognized that the new federal habeas consequence jeopardizes both a state procedural default rule and the state's power and right to pass upon constitutional claims in the first instance. Third, it acknowledged that federal courts sitting in habeas corpus review of final Pennsylvania convictions may review claims of trial counsel ineffectiveness not raised by postconviction counsel on the merits, in the first instance, as an "`equitable'" matter.32

However, the Pennsylvania court declined to modify its framework for collateral review of criminal convictions. It recognized that the question of "whether to take measures to otherwise account for the concerns of Martinez" is one of policy.33 It elected to await either the action of its state legislature or a case where the issue was properly joined.

Similarly, we conclude that such matters of policy should be addressed in the first instance to the Legislature. Our Legislature has enacted postconviction relief limited to a single proceeding. Neb.Rev.Stat. § 29-3001 (Cum.Supp.2012) permits a prisoner to file a verified motion asking the sentencing court to vacate or set aside the sentence and stating the grounds entitling him or her to relief. It expressly authorizes a court to reject a second or successive motion for similar relief.34 Whether Nebraska should provide a second round of collateral review as of right to capture claims of ineffective assistance of trial counsel which have been defaulted in the initial postconviction proceeding is a matter for the Legislature. It should make that decision in light of the consequences that follow from Martinez as accurately summarized by the Pennsylvania court. But until that time, this court continues to enforce our procedural rules in accordance with our well-settled postconviction jurisprudence. Accordingly, we reject Hessler's argument regarding Martinez and affirm the district court's denial of an evidentiary hearing on claims 6 through 9, 11, 12, and 14.

2. DENIAL OF CORAM NOBIS RELIEF

Hessler also sought relief under the common-law writ of error coram nobis. The common-law writ of error coram nobis exists in this state under Neb. Rev.Stat. § 49-101 (Reissue 2010), which adopts English common law to the extent that it is not inconsistent with the Constitution of the United States, the organic law of this state, or any law passed by our Legislature.35 The purpose of the writ of error coram nobis is to bring before the court rendering judgment matters of fact which, if known at the time the judgment was rendered, would have prevented its rendition.36 It enables the court to recall some adjudication that was made while some fact existed which would have prevented rendition of the judgment but which, through no fault of the party, was not presented.37 The burden of proof in a proceeding to obtain a writ of error coram nobis is upon the applicant claiming the error, and the alleged error of fact must be such as would have prevented a conviction.38 It is not enough to show that it might have caused a different result.39

But Hessler's second motion for postconviction relief failed to allege any fact not presented in the prior proceedings which would have prevented his convictions. As previously noted, the claims raised in the present motion shared three common themes: mental competency, errors or misconduct at trial, and ineffective assistance of counsel. As to his mental competency, Hessler alleged that the trial court was not presented with information regarding his various mental illnesses and the medications he was taking at the time of trial. But in his first postconviction action, this information was adduced at an evidentiary hearing, and we concluded that the record affirmatively showed that Hessler had met the legal standard of competency.40

As to his claims of errors or misconduct at trial and ineffective assistance of counsel, such claims were inappropriate for coram nobis relief. The writ of error coram nobis is not available to correct errors of law.41 We find no error in the district court's denial of a writ of error coram nobis.

VI. CONCLUSION

Except for Hessler's argument citing to Martinez, the claims raised in Hessler's second motion for postconviction relief either were litigated in the prior proceedings or were known and could have been litigated. As such, they were procedurally barred. And Hessler's claim of ineffective assistance of postconviction counsel, relying upon Martinez, was without constitutional support. He similarly failed to raise any basis warranting coram nobis relief. We affirm the denial of Hessler's second motion for postconviction relief and writ of error coram nobis.

AFFIRMED.

Heavican, C.J., not participating.