OPINION

In 1967 Tillery was convicted by an Arizona court of assault with a deadly weapon and of armed robbery. Tillery exhausted his available state remedies, the Arizona Supreme Court affirming his conviction in State v. Tillery, 107 Ariz. 34 , 481 P.2d 271 , cert. denied, 404 U.S. 847 , 92 S.Ct. 151 , 30 L.Ed.2d 84 (1971). Tillery filed a petition for a writ of habeas corpus in the District Court, pursuant to 28 U.S.C. § 2241 (c). Upon a denial of his petition, Tillery appeals.

Here, Tillery raises the same two issues urged in the court below. He contends (1) that he was denied a fair trial when the trial court failed, sua sponte, to conduct an evidentiary hearing on Tillery’s competency to stand trial and (2) that he was deprived of his constitutional right to testify in his own behalf. Because the issue is dispositive of the appeal, we consider only Tillery’s contention concerning the trial court’s failure to conduct an evidentiary hearing on his mental capacity.

During the course of the trial Tillery exhibited erratic and irrational behavior. The court was aware that Tillery yelled and screamed from his jail cell throughout the nights. In open court, Tillery laughed at the jury and made gestures at the bailiff. On April 28, 1967, the fourth day of the trial, after another vocal outburst by Tillery, the court admonished him to be quiet. Til-lery thereupon ripped off his tie and shirt. He was removed from the courtroom screaming and the trial was recessed. In chambers, in the presence of the attorneys for both sides, the court stated:

The court ordered Dr. Norman D. Duley, a qualified psychiatrist, to examine Til-lery.

On April 30, two days after the outburst, Tillery was examined by Dr. Du-ley. Dr. Duley’s report, which was filed with the court, stated that Tillery did not show any signs of “psychosis or impairment of thinking processes.” It was the psychiatrist’s opinion that Tillery was competent to stand trial and to aid in his own defense. Upon receiving the report, the court decided to proceed with the trial without conducting an eviden- *1058 tiary hearing. 2 Defense counsel did not object to the court’s action.

Before appearing in court on May 3d, Tillery refused to put on his shoes and socks. The deputies then completed dressing him and were escorting the defendant to the courtroom when Tillery broke away from them. He suddenly butted his head through a glass window, receiving superficial wounds. Dr. J. L. Sitterley, M. D., then examined Tillery and testified before the court as to his observations. Although Dr. Sitterley did not believe there was “any psychotic episode,” he further testified:

Even though the court then indicated that it was ordering Dr. Duley to examine Tillery again, the record at trial is silent as to the result of any subsequent examination.

One of Tillery’s attorneys also testified concerning the defendant’s condition of May 3d. Both defense counsel and the court were concerned- that Til-lery might demand to testify on his own behalf. Apparently they feared that, should Tillery take the stand, he would seriously prejudice his case by his emotional and erratic behavior. Defense counsel informed the court that Tillery, on May 3d, had demanded “in his wild-eyed ways” to take the stand, but the attorney stated that Tillery, at that time, “was very incoherent [and] very irrational.” He further opined that Tillery did not know what he was doing. Although the attorney’s testimony was directed at Tillery’s demand to testify, the evidence was relevant to Tillery’s mental capacity to stand trial. •

From the foregoing evidence before the trial court, we conclude that Pate v. Robinson, 383 U.S. 375 , 86 S.Ct. 836 , 15 L.Ed.2d 815 (1966) required the court to conduct an evidentiary hearing concerning the defendant’s competency to stand trial. It is elementary that the conviction of an accused while he is incompetent violates his due process rights. Pate v. Robinson, supra at 378 , 86 S.Ct. 836 , 15 L.Ed.2d 815 , citing Bishop v. United States, 350 U.S. 961 , 76 S.Ct. 440 , 100 L.Ed. 835 (1956). A defendant is considered competent to stand trial if he “ ‘has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding [and if] he. has a rational as well as factual understanding of the proceedings against him.’ ” Dusky v. United States, 362 U.S. 402 , 80 S.Ct. 788 , 4 L.Ed.2d 824 (1960), quoted in Pate v. Robinson, 383 U.S. at 388 , 86 S.Ct. at 843 (dissenting opinion). In Pate , the Supreme Court held that when the evidence at trial raises a bona fide doubt as to an accused’s competency to stand trial, the trial court, on its own motion if necessary, must conduct an evidentiary hearing to resolve that doubt.

This Court has previously explained that Pate requires an evidentiary competency hearing any time there is “substantial evidence” that the defendant may be mentally incompetent to stand trial. Moore v. United States, 464 F.2d 663 (9th Cir. 1972). We there stated:

Moore v. United States, supra at 666; see Rhay v. White, 385 F.2d 883 (9th Cir. 1967).

The evidence at trial included Tillery’s outbursts in the courtroom and his irrational behavior while in confinement. The trial judge, after witnessing Tillery’s conduct, was convinced that Tillery was psychotic and ordered a psychiatric examination. 3 Both defense counsel and Dr. Sitterley related facts which indicated that Tillery was unable to aid in his own defense, and Dr. Sitterley even suggested that Tillery be sedated during the trial. It is significant, too, that both defense counsel and the court were convinced that Tillery was not mentally capable of testifying in his own behalf without seriously prejudicing his case. We are persuaded that there was substantial evidence that Tillery may have been mentally incompetent to stand trial. Although there was information indicating that Tillery was in fact competent, such conflicting evidence can only be. resolved by an evidentiary hearing.

Although defense counsel did not object to the procedure followed at trial, the state cannot rationally contend that Tillery waived his right to an eviden-tiary hearing. “It is contradictory to argue that a defendant may be incompetent, and yet knowingly or intelligently ‘waive’ his right to have the court determine his capacity to stand trial.” Pate v. Robinson, 383 U.S. at 384 , 86 S.Ct. at 841 , citing Taylor v. United States, 282 F.2d 16, 23 (8th Cir. 1960).

Since Tillery was not afforded the required evidentiary hearing at his trial more than six years ago, the writ of habeas corpus must issue. Because of the difficulty of retroactively determining one’s competency to stand trial, after the lapse of so many years, Tillery must be discharged unless Arizona elects to retry him within a reasonable time. Pate v. Robinson, supra; Moore v. United States, supra.

Upon remand, the District Court will hold Tillery’s petition in abeyance for a reasonable period, not exceeding sixty days, in order to afford Arizona authorities an opportunity to retry Tillery, should they choose to do so.

Reversed and remanded, with directions.

. Former Ariz.R.Crim.P. 250(A) (reenacted and modified as 17 Ariz.Rev.Stat.Ann. Rules 11.2, 11.3, 16.4 (1973)) provided in pertinent part:

. The Arizona Supreme Court ruled that there was no “manifest abuse of discretion” by the trial judge in refusing to hold an evi-dentiary hearing under former Rule 250. State v. Tillery, 107 Ariz. 34 , 481 P.2d 271 (1971).

. One court lias suggested that whenever a trial court orders a psychiatric examination as to the defendant’s present competency, then a bona fide doubt is immediately established as a matter of fact and as a matter of law. Brizendine v. Swenson, 302 F.Supp. 1011, 1019 (W.D.Mo.1969). We need not decide whether the trial court’s order for a psychiatric examination, standing alone, reflected such substantial doubt as to Tillery’s competency as to require, of itself, that a competency hearing be conducted.