I
Celebrezze, C.J.Appellant first contends that, pursuant to R.C. 2945.42,1 his wife was not competent to testify against him at trial. Appellant further argues that allowing his wife to testify concerning privileged marital communications was substantial, prejudicial error in contravention of R.C. 2945.42. Although we reject the first of these contentions, we find merit in the second.
The Rules of Evidence which now govern court proceedings have *148superseded many of the prior statutes which were procedural in nature. Spousal competency is distinguished from spousal privilege, and each issue is now treated in a separate rule.
Evid. R. 601(B)2 is a rule of procedure which, as the Staff Note states, is intended to supersede R.C. 2945.42 as to spousal competency. Rule 601(B) provides that one spouse is not competent to testify against the other spouse unless the crime was committed against the testifying spouse or the child of either. In the case sub judice, the victim of this crime was the twenty-year-old child of appellant’s wife. As the Staff Note also indicates, this rule was drafted broadly enough to encompass both minor and adult children. Therefore, it is clear that appellant’s wife was at least competent to testify against him pursuant to Evid. R. 601(B). Appellant’s first contention is thus without merit.
However, the Rules of Evidence in Ohio are limited by Section 5(B), Article IV of the Ohio Constitution to procedural effect only. Evid. R. 601 is inapplicable to the substantive spousal privilege, as the Staff Note emphasizes:
“Rule 601 is directed to competency. Rule 501 is directed to privilege and is a general rule serving to maintain R.C. 2945.42 as to privilege. ÍÍ* * *
“Rule 601(B) supersedes R.C. 2945.42 as to spousal competency, but not as to spousal privilege.”
The spousal privilege contained in this statute is preserved by Evid. R. 501, which states:
“The privilege of a witness, person, state or political subdivision thereof shall be governed by statute enacted by the General Assembly or by principles of common law as interpreted by the courts of this state in the light of reason and experience.”
Here, again, the Staff Note to the rule reaffirms the continuing precedence of the spousal privilege contained in R.C. 2945.42:
“Rule 501 * * * leaves the matter of privileges essentially undisturbed. Statutory and case law pronouncements respecting privileges continue in force by operation of the rule.”
R.C. 2945.42, which codifies the spousal privilege in a criminal trial, thus creates a substantive right which cannot be abridged by this court or any other. The pertinent portion of this statute reads as follows:
“* * * Husband or wife shall not testify concerning a communication made by one to the other, or act done by either in the presence of the other, during coverture, unless the communication was made or act done • *149in the known presence or hearing of a third person competent to be a witness, or in case of personal injury by either the husband or wife to the other, * * * or neglect or cruelty of either to their children under eighteen years of age or their physically or mentally handicapped child under twenty-one years of age * *
Thus, although a spouse may be competent to testify in a criminal trial, R.C. 2945.42 confers a substantive right upon the accused to exclude privileged spousal testimony concerning a confidential communication made or act done during coverture unless a third person was present or one of the other specifically enumerated exceptions contained in the statute is applicable.
Although appellee admits that testimony forbidden by R.C. 2945.42 was allowed at trial, the state asserts that appellant’s right to exclude privileged testimony was abrogated by this court in State v. Mowery (1982), 1 Ohio St. 3d 192. This assertion is not correct.
The Mowery majority, in dictum, discussed the rule concerning the privilege to exclude adverse spousal testimony as set forth by the United States Supreme Court in Trammel v. United States (1980), 445 U.S. 40. In Trammel, applying federal common-law principles, the United States Supreme Court held that in federal criminal trials, the witness-spouse was vested with this testimonial privilege and could decide whether to testify adversely to the defendant-spouse. Trammel is inapposite to the case sub judice. In Trammel there was no federal statute explicitly excluding testimony as to confidential marital communications or acts such as R.C. 2945.42. Secondly, the Trammel decision was not even necessary to our conclusion in Mowery. No privilege was found in Mowery because of the presence of a third party during the commission of the crime by the defendant-spouse. As Mowery holds in paragraph two of the syllabus:
“An accused may not assert a privilege under R.C. 2945.42 to preclude a spouse from testifying with respect to a crime committed against a third person, where the crime is committed in the known presence of such third person, as well as in the presence of the testifying spouse.” (Emphasis added.)
Thus, the Mowery court began and ended its application of the spousal privilege by looking to the controlling statute, R.C. 2945.42, as we must also do in the case sub judice.
Turning to this statute, we can find no exception permitting the testimony of appellant’s wife. There was no third person present or within hearing during this conversation as there was in Mowery. The spouse was not the victim of this crime and was not present during its commission. The victim of this crime was not a child of the spouse under the age of eighteen, nor was the victim a physically or mentally handicapped child under the age of twenty-one at the time of this killing. Thus, the trial court erred in allowing appellant’s wife to testify concerning privileged marital communications.
*150We must now determine whether that error was harmless, i.e., error which did not affect a substantial right of the accused. Crim. R. 52(A).3 We conclude that the admission of this testimony undermined appellant’s constitutional right to a fair trial, thus bringing the case sub judice outside the harmless error doctrine.
It is difficult to minimize the prejudicial impact of the testimony of appellant’s wife. The fact is that this spouse was erroneously permitted to tell the jury about confidential marital communications between herself and appellant on the very morning the state alleges this murder took place. Appellant’s wife stated that appellant was enraged and accused the victim of stealing family food stamps. Appellant’s wife also testified that appellant acted like a crazy man, was so angry at the victim that he drove their car erratically, and used vile language when referring to the victim. This testimony from the accused’s own wife surely had an influence on the jury.
Further, this testimony supplied the state’s most compelling evidence of motive in a case which otherwise rested on circumstantial evidence against appellant. The state produced no evidence directly linking appellant to this killing. The blood found in the victim’s bedroom could not be identified as his. No evidence was presented linking the hammer to the crime. Blood on the knife could not even be identified as human blood. The coroner could not state that the knife found in appellant’s bedroom was the murder weapon and testified only that the victim’s wounds were not inconsistent with the type of wounds that could have been made by that knife. There was no proof that the blood found on appellant’s discarded clothes was that of the victim. Experts could not state with certainty that carpet fibers from those clothes matched the carpet in the victim’s bedroom. Thus, although motive is not essential to a conviction, this court has recognized that “[wjhere, in a murder case, the evidence is purely circumstantial, the identification of the killer is not shown by direct evidence, and, therefore, his identity must be proved, motive or lack thereof becomes an important question * * *.” State v. Lancaster (1958), 167 Ohio St. 391 [5 O.O.2d 28], paragraph three of the syllabus.
It is evident from the foregoing that the testimony of appellant’s wife played a prominent role in his conviction. The United States Supreme Court, in Chapman v. California (1967), 386 U.S. 18, 23-24, stated that “[a]n error in admitting plainly relevant evidence which possibly influenced the jury * * * cannot * * * be conceived of as harmless.” Under the court’s test in Chapman, in order to sustain a conviction the reviewing court must be able to declare a belief that the error was harmless beyond a reasonable doubt. There must be other overwhelming evidence of guilt. *151Harrington v. California (1969), 395 U.S. 250, 254; State v. Maurer (1984), 15 Ohio St. 3d 239, 264.
This court has consistently followed Chapman. In State v. Bayless (1976), 48 Ohio St. 2d 73, 106 [2 O.O.3d 249], vacated in part on other grounds (1978), 438 U.S. 911, we held that “[e]rror in the admission of evidence is harmless if there is no reasonable possibility that the evidence may have contributed to the accused’s conviction.” In State v. Ferguson (1983), 5 Ohio St. 3d 160, 166, fn. 5, cited with approval in State v. Maurer supra, at 264, we stated that “the cases where imposition of harmless error is appropriate must involve either overwhelming evidence of guilt or some other indicia that the error did not contribute to the conviction.”
Upon a thorough review of the record, we simply cannot state in good conscience that the error in the admission of this privileged testimony was either harmless beyond a reasonable doubt, did not have an impact on the jury, or did not contribute to appellant’s conviction in any meaningful degree.4 We must, therefore, reverse appellant’s conviction.
II
Although we have concluded that the error in admitting privileged spousal testimony alone warrants reversal, appellant also raises several additional propositions of law which we will now address.
Appellant first claims that his wife was incompetent to identify, from the witness stand, a bloodstained shirt and pair of pants as his. Appellant also asserts that this identification was based on his wife’s testimony that, during their marriage, she had given the shirt to appellant and had seen him repair the zipper on the pants, thus bringing this testimony within the marital privilege.
These contentions are without merit. We have previously stated in this opinion that appellant’s wife was competent to testify. We also do not think that the identification of a shirt and pants which appellant presumably wore on numerous occasions in the presence of his family and other third parties concerned a communication or act excluded by the marital privilege. Appellant’s wife’s testimony in this regard was thus properly admitted.
*152Appellant next contends that the trial court abused its discretion by admitting into evidence several color photographs of the victim’s body and a color photograph of an x-ray of the victim’s skull. Appellant contends the prejudice caused by admission of these “gruesome” photographs outweighed their probative value and thus should not have been admitted pursuant to Evid. R. 403.5
Under Evid. R. 403 the admission or exclusion of such photographic evidence is left to the court’s discretion in balancing the probative value against the danger of unfair prejudice. We stated in State v. Maurer, swpra, at 265 that “the mere fact that a photograph is gruesome or horrendous is not sufficient to render it per se inadmissible.” The photographs in the case sub judice depicted the scene in the basement where the victim’s body was found and included a photograph of the victim’s body taken during the coroner’s examination. The photograph of the x-ray depicted the damage to the victim’s skull. Each of these photographs illustrated testimony by both lay and expert witnesses. As we observed in Maurer, supra, at 265, “[s]uch illustrative photographs are generally admissible.” We cannot say that the trial judge abused his discretion in finding that these photographs were admissible because their probative value outweighed any prejudice to appellant. This proposition of law is not well-taken.
Appellant next urges as error the prosecutor’s comment, in closing argument, on appellant’s post-arrest silence prior to trial. In essence, the prosecutor pointed out to the jury that appellant had not given his version of what happened until he testified at trial. The prosecutor used this post-arrest silence to attack appellant’s credibility.
Such a comment is clearly improper under Doyle v. Ohio (1976), 426 U.S. 610, in which the United States Supreme Court held that the use for impeachment of appellant’s post-arrest silence after receiving Miranda warnings was violative of the Due Process Clause of the Fourteenth Amendment. In Doyle, the prosecutor made numerous references during cross-examination and closing argument to the defendant’s failure to explain his actions prior to his testimony at trial. The court held in Doyle, supra, at 617-618:
“Silence in the wake of these warnings may be nothing more than the arrestee’s exercise of these Miranda rights. Thus, every post-arrest silence is insolubly ambiguous because of what the State is required to advise the person arrested. * * * Moreover, while it is true that the Miranda *153warnings contain no express assurance that silence will carry no penalty, such assurance is implicit to any person who receives the warnings. In such circumstances, it would be fundamentally unfair and a deprivation of due process to allow the arrested person’s silence to be used to impeach an explanation subsequently offered at trial.”
We also note, however, that appellant did not object at the time the prosecutor’s comment was made. Thus, in the absence of plain error affecting substantial rights, Crim. R. 52(B),6 this court need not consider this proposition of law.
In State v. Long (1978), 53 Ohio St. 2d 91 [7 O.O.3d 238], paragraph three of the syllabus, we held that “[n]otice of plain error * * * is to be taken with the utmost caution, under exceptional circumstances and only to prevent a manifest miscarriage of justice.” With this admonition in mind, we find that the single comment on appellant’s post-arrest silence does not reach the serious constitutional impairment of the repeated references to such silence as were made by the prosecutor in Doyle, supra.
While we cannot condone even an isolated reference to a defendant’s post-arrest silence, we do not find plain error in the prosecutor’s remark in the case sub judice. Thus, appellant’s proposition of law is not well-taken.
Appellant also contends that the prosecutor made repeated comments, designed to appeal to the jury’s racial or religious prejudices, which denied him a fair trial. We first observe that the comments which appellant now claims are error also were not objected to at trial. Thus, again, in the absence of plain error, this court need not address this issue.
Certainly, appeals to racial or religious prejudices are improper conduct on the part of a prosecutor and may exert such a substantial influence on the result at trial that reversal is required. United States v. Grey (C.A.6, 1970), 422 F.2d 1043, 1046. In the cause sub judice, however, the prosecutor’s cross-examination of appellant properly sought to impeach appellant’s credibility.
Appellant had, on direct examination, portrayed himself as a devout Moslem and emphasized his concern for the spiritual and physical well-being of his wife and her children. The prosecutor then fairly sought to point out the contradictions between appellant’s testimony and his admitted gambling activities and visits to after-hours establishments for that purpose. If appellant put his religious character in issue, then, pursuant to Evid. R. 404(A)(1),7 the prosecutor could rebut such evidence. We do not *154find reversible plain error in the prosecutor’s conduct on cross-examination of appellant.
Finally, with regard to appellant’s claims regarding prosecutorial misconduct, appellant asserts prejudicial error in the prosecutor’s characterization of appellant in closing argument as a “hypocrite” and “the biggest liar that’s taken the stand in a long time.” Again, the record reflects that no objections were taken at the time these remarks were made.
We first observe that the Code of Professional Responsibility as well as the American Bar Association’s Standing Committee on Association Standards for Criminal Justice directly forbid comments by'an attorney or prosecutor which express his personal opinion as to the credibility of a witness.8 In the leading case of Berger v. United States (1935), 295 U.S. 78, 88, the high court recognized that a prosecutor plays a special role as “the representative not of an ordinary party to a controversy, but of a sovereignty whose obligation to govern impartially is as compelling as its obligation to govern at all; and whose interest, therefore, in a criminal prosecution is not that it shall win a case, but that justice shall be done.”
This court has, however, also granted prosecutors wide latitude in closing argument. State v. Maurer, supra, at 269. The effect of any prosecutorial misconduct “ ‘must be considered in the light of the whole case.’ ” Id. at 266. We must also remember that “ ‘[i]f every remark made by counsel outside of the testimony were grounds for a reversal, comparatively few verdicts would stand, since in the ardor of advocacy, and in the excitement of trial, even the most experienced of counsel are occasionally carried away by this temptation.’ ” Id. at 267, quoting Dunlop v. United States (1897), 165 U.S. 486, 498. Thus, while the prosecutor’s remarks in the case sub judiee were improper, we do not consider these *155remarks standing alone to have risen to the level of plain error requiring reversal.
Appellant next alleges as error the trial court’s failure to hold a hearing on his timely challenge to the array of jurors pursuant to Crim. R. 24(E).9 Appellant’s motion to dismiss the array was made orally, and prior to the voir dire of prospective jurors in his trial. The motion, however, was based on the mere bald assertion by appellant’s attorney that the county commissioners had excluded minorities from the panel. No evidence whatsoever in support of this contention was produced for the trial court or for the record.
Two courts have faced similar challenges to an array by a criminal defendant. In Frazier v. United States (1948), 335 U.S. 497, the defendant was charged with a violation of a federal narcotics Act and faced a jury composed entirely of federal employees. Petitioner moved that the panel be stricken on grounds his Sixth Amendment right to a trial by an impartial jury was violated. This oral motion was based on the assertion of petitioner’s counsel that the procedure used in selecting prospective jurors was “irregular.” The Supreme Court held that this motion, supported solely by counsel’s unsworn statement and without any proof or offer of proof, was without merit. Id. at 503-504.
In State v. Wright (1976), 290 N.C. 45, 224 S.E. 2d 624, the defendant, who was black, faced an all-white panel of prospective jurors. Defense counsel moved to dismiss the panel “for the reason that there are no blacks.” The trial court summarily denied the motion. On appeal, defendant contended that he should have been given the opportunity to show that blacks had been systematically excluded from the panel. The North Carolina Supreme Court rejected this contention. The court noted that defense counsel had been appointed some thirteen months prior to trial and had ample time and opportunity to investigate the exclusion of blacks from juries in that county. Yet, counsel had offered no evidence in support of his motion and had not requested additional time in which to procure evidence. Absent any more than the unsworn allegation made in defendant’s motion, the court found no error in the trial court’s refusal to hold a hearing. Id. at 49, 224 S.E. 2d at 627.
The case sub judice presents a situation much like that found in Frazier and Wright, supra. Appellant’s counsel made an unsworn allegation, unsupported by any evidence, that minority persons had been excluded from the jury panel. Absent any evidence or even a proffer for the record in support of this motion, we find no error in the trial court’s failure to hold a hearing on appellant’s challenge to the array.
*156Appellant next asserts as error the trial court’s failure to hold a hearing on his competency to stand trial after appellant announced he would not continue his testimony. Although appellant did not raise the issue of his competency at this time, he claims that the court, sua sponte, should have held a hearing due to the sudden change in his attitude.
R.C. 2945.37(A)10 states that either the prosecutor, defense or the court may raise the issue of a defendant’s competency to stand trial. If this issue is raised after trial has begun, the court shall hold a competency hearing only for good cause shown. Thus, the decision as to whether to hold a competency hearing once trial has commenced is in the court’s discretion.
The test to determine whether a defendant is competent to stand trial was set forth in Dusky v. United States (1960), 362 U.S. 402, where the high court stated “the ‘test must be whether he has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding — and whether he has a rational as well as a factual understanding of the proceedings against him.’ ”
In State v. Chapin (1981), 67 Ohio St. 2d 437, 441-442 [21 O.O.3d 273], this court recognized that objective indications such as medical reports, specific references by defense counsel to irrational behavior, or the defendant’s own conduct during the trial would indicate “good cause shown” for the allowance of a competency hearing after trial had begun. In holding that good cause had not been shown, the court noted, at 441, fn. 1, “[t]he record is devoid of any other subtle nuances or questionable actions by the appellee throughout this long trial, which is supportive of appellant’s argument that an additional hearing is unnecessary.”
In the case sub judice, the record is also barren of any questionable actions by appellant prior to his refusal to continue his cross-examination. Appellant had testified at length, and articulately, on direct examination and had exhibited no strange behavior either prior to or during his cross-examination.
When appellant refused to continue his testimony, the court immediately dismissed the jury and asked defense counsel if he wished to confer with his client. Defense counsel informed the court that he had conferred with appellant at length the evening before and had no inkling of a problem. There was no suggestion by defense counsel that appellant had suddenly become incompetent to stand trial. The trial court conferred with appellant at length in order to determine the reasons for his refusal to testify. The court also carefully informed appellant of the consequences of his failure to continue testifying. Appellant indicated that he fully *157understood those consequences. The court had observed appellant’s conduct throughout this trial and, as previously stated, the record does not contain the slightest suggestion that appellant behaved in a manner which would have called any lack of competency to the attention of the court.
Appellant’s sudden change of mind was unfortunate, but there is no evidence in the record to convince us that he did not have a reasonable degree of rational understanding of the nature and consequences of his refusal to testify further. Absent any objective indications of “good cause shown,” the trial court did not err in failing to hold a hearing into appellant’s competency after this trial had begun.
Lastly, appellant contends that the trial court erred in denying his motion for acquittal because the state’s case did not preclude all reasonable theories of innocence. Because we are reversing appellant’s conviction, we need not now address this proposition of law.
Accordingly, we reverse the judgment of the court of appeals by reason of the erroneous admission of the privileged testimony of appellant’s wife and remand this cause for a new trial in accordance with this opinion.
Judgment reversed and cause remanded.
Sweeney, Locher, C. Brown and Wright, JJ., concur. Holmes and Douglas, JJ., concur in part and dissent in part.R.C. 2945.42 provides:
“No person is disqualified as a witness in a criminal prosecution by reason of his interest in the prosecution as a party or otherwise, or by reason of his conviction of crime. Husband and wife are competent witnesses to testify in behalf of each other in all criminal prosecutions, and to testify against each other in all actions, prosecutions, and proceedings for personal injury of either by the other, bigamy, or failure to provide for, neglect of, or cruelty to their children under eighteen years of age or their physically or mentally handicapped child under twenty-one years of age. A spouse may testify against his spouse in a prosecution under sections 2903.11 to 2903.13, 2919.21, 2919.22, or 2919.25 of the Revised Code for cruelty to, neglect of, or abandonment of such spouse. Such interest, conviction, or relationship may be shown for the purpose of affecting the credibility of such witness. Husband or wife shall not testify concerning a communication made by one to the other or act done by either in the presence of the other, during coverture, unless the communication was made or act done in the known presence or hearing of a third person competent to be a witness, or in case of personal injury by either.the husband or wife to the other, or bigamy, or failure to provide for, or neglect or cruelty of either to their children under eighteen years of age or their physically or mentally handicapped child under twenty-one years of age, or neglect or abandonment of such spouse under such sections. The presence or whereabouts of the husband or wife is not an act under this section. The rule is the same if the marital relation has ceased to exist.”
Evid. R. 601 states:
“Every person is competent to be a witness except:
“(B) A spouse testifying against the other spouse charged with crimes except crimes against the testifying spouse or the children of either * *
Crim. R. 52(A) defines “harmless error” and reads as follows: “Any error, defect, irregularity, or variance which does not affect substantial rights shall be disregarded.”
We are also mindful that our role upon review of this case is not to sit as the supreme trier of fact, but rather to assess the impact of this erroneously admitted testimony on the jury. In writing about the court’s function on federal appellate review, Justice John Paul Stevens’ observation is particulary appropriate:
“ ‘[I]t is not the appellate court’s function to determine guilt or innocence * * *. Nor is it to speculate upon probable reconviction and decide according to how the speculation comes out * * *. [T]he question is, not were [the jury] right in their judgment, regardless of the error or its effect upon the verdict. It is rather what effect the error had or reasonably may be taken to have had upon the jury’s decision. The crucial thing is the impact of the thing done wrong on the minds of other men, not on one’s own, in the total setting.’ ” United States v. Hasting (1983), 461 U.S. 499, 516, Stevens, J., concurring (quoting Kotteakos v. United States [1946], 328 U.S. 750, 763-764).
Evid. R. 403 reads as follows:
“(A) Exclusion mandatory. Although relevant, evidence is not admissible if its probative value is substantially outweighed by the danger of unfair prejudice, of confusion of the issues, or of misleading the jury.
“(B) Exclusion discretionary. Although relevant, evidence may be excluded if its probative value is substantially outweighed by considerations of undue delay, or needless presentation of cumulative evidence.”
Crim. R. 52(B) defines plain error and reads as follows:
“Plain errors or defects affecting substantial rights may be noticed although they were not brought to the attention of the court.”
Evid. R. 404(A)(1) states in part:
“(A) Character evidence generally. Evidence of a person’s character or a trait of his character is not admissible for the purpose of proving that he acted in conformity therewith on a particular occasion, subject to the following exceptions:
*154“(1) Character of accused. Evidence of a pertinent trait of his character offered by an accused, or by the prosecution to rebut the same is admissible; however, in prosecutions for rape, gross sexual imposition, and prostitution, the exceptions provided by statute enacted by the General Assembly are applicable.” (Emphasis added in part.)
DR 7-106 of Ohio’s Code of Professional Responsibility provides in relevant part:
“(C) In appearing in his professional capacity before a tribunal, a lawyer shall not:
“(4) Assert his personal opinion as to the justness of a cause, as to the credibility of a witness, * * * or as to the guilt or innocence of an accused * *
The American Bar Association’s Standing Committee on Association Standards for Criminal Justice has developed guidelines, one of which states that “[i]t is unprofessional conduct for the prosecutor to express his or her personal belief or opinion as to the truth or falsity of any testimony or evidence or the guilt of the defendant.” Standard 3-5.8(b), 1 ABA Standards for Criminal Justice (2 Ed. 1980) 3-87. The accompanying commentary explains:
“Expressions of personal opinion by the prosecutor are a form of unsworn, unchecked testimony and tend to exploit the influence of the prosecutor’s office and undermine the objective detachment that should separate a lawyer from the cause being argued.” Id. at 3.89.
Crim. R. 24 states in pertinent part: “(E) Challenge to array. The prosecuting attorney or the attorney for the defendant may challenge the array of petit jurors on the ground that it was not selected, drawn or summoned in accordance with law. A challenge to the array shall be made before the examination of the jurors pursuant to subdivision (A) and shall be tried by the court.”
R.C. 2945.37(A) states in pertinent part: “In a criminal action in a court of common pleas or municipal court, the court, prosecutor, or defense may raise the issue of the defendant’s competence to stand trial. If the issue is raised before trial, the court shall hold a hearing on the issue as provided in this section. If the issue is raised after trial has begun, the court shall hold a hearing on the issue only for good cause shown.”