Defendant appeals her conviction of theft and assault arising from a shoplifting incident after which she stabbed a store employee who confronted her. The case was tried to the court without a jury. She assigns as error the denial of her motion for mistrial based on claimed misconduct of the prosecutor in advising prospective witnesses that “it would be better if we didn’t say anything” to the defense. The Court of Appeals did not express approval of the prosecutor’s advice, but affirmed the conviction.1
The state called the store manager and the assault victim as witnesses. The manager testified that he refused to discuss the case with defense investigators before trial because it was “against store policy” to do so. The victim testified:
“Q [By defense attorney] Did somebody call you on the telephone, say that he was an investigator from the Public Defender’s Office, that he represented a Ms. Rosie York and that he wanted to talk about this case with you? i(
“A [By Employe] Yes.
“Q What did you tell him?
“A I said, ‘No, I won’t talk about it until the trial.’
“Q Did somebody tell you to say that?
“A No.
“Q That was just your idea?
“A Yeah.
“Q Mr. Ortner never mentioned that to you?
“A (No audible response.)
“Q It’s not a store policy or anything like that?
“A No. They said it would be better if we didn’t say anything, but I wouldn’t have anyway.
“Q Who said that?
“A The DA.
“Q [A deputy district attorney] told you that?
*538“A Yeah, he said specifically we had our choice whether or not we wanted to. And I chose not to.
“Q But he said it was better if you didn’t say anything?
“A No, he didn’t. He said — he said —
“Q Go ahead.
“A He said it was our choice whether we wanted to or didn’t want to, and it was up to us.
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“Q [By Defense Attorney] My question is: You said ‘they’ said that, meaning somebody from the District Attorney’s Office said it would be better if you didn’t say anything. We’re just trying to find out if that’s what they said. Who was the ‘they’?
“A [By Employe] Uh-huh, they said that. The DA’s Office, [a deputy district attorney] — they told us. The DA’s Office, * * *, who we had contact with. He said that it was our choice whether or not we wanted to say anything, that if we said anything, it can be used for us or against us at •— it’s better off if we don’t say anything until the trial, and then we talk about it then. And then it will come up then.” (Emphasis added.)
Defendant’s motion for mistrial was denied. Upon a motion for reconsideration, the prosecutor testified that he had told the two witnesses it was their choice whether to talk to attorneys for either side. He further testified that he could not and would not tell them not to talk to the defense. He denied telling the witnesses it would be better not to do so. The trial court nevertheless found:
“* * * The Court finds based on this record — and I am not now trying to say verbatim what was said — but the Court finds that the prosecutor did state to two prosecution witnesses that they might be contacted by defense counsel or representatives of defense counsel; that he told them that he was not telling them that they should not talk to the person, but that he did tell them that if they were interviewed, that their interview would either be taped or otherwise recorded and that their statements could be used against them at trial and that it would be better if they didn’t say anything.
“Based on this entire record, the Court does not feel under these circumstances that that constitutes misconduct in this case and does not find that there is a basis for a mistrial and continues its decision as before. Therefore, *539the motion for reconsideration is denied.” (Emphasis added.)
The finding of fact is binding on appeal. The conclusion that the prosecutor’s act was not “misconduct” is a decision of law which is subject to appellate scrutiny. We allowed review to consider two questions: first, whether it is improper for a prosecutor to encourage a witness to refuse requests for interviews or information from the defense, and second, if this is improper, what remedies are available to the defendant.
I
It is improper for a prosecutor to instruct prospective witnesses that they should not talk to the defense
A district attorney’s duty to prosecute persons charged with crime does not authorize the prosecutor to frustrate, by improper means, the legitimate efforts of the defense to defend the case. Clearly, efforts of the defense to interview prospective witnesses are legitimate activities of a defense attorney.2 The pivotal question, and the principal issue in this case, is whether it is improper for a prosecutor to impede defense efforts to interview prospective witnesses by instructing them not to talk to the defense attorney, or as in this case, by telling them (as the trial court found) “* * * that it would be better if they didn’t say anything.”
Although no statute or rule expressly forbids such prosecutorial conduct, we believe that both statutory law and disciplinary rules, examined collectively, leave little doubt of this state’s policy toward the principle of non-interference with defendant’s access to witnesses. ORS 135.815(1) requires the district attorney, prior to trial, to disclose to the defendant materials of various kinds, including “[t]he names and addresses of persons whom he intends to call as witnesses at any state [sic] of the trial.” The section continues by requiring the district attorney to disclose the written or recorded statements of such witnesses or memoranda of their oral statements. ORS 135.815(2). It *540hardly is consistent with the policy of this section to require the prosecutor to disclose to the defense the “names and addresses” of witnesses, on the one hand, and on the other, to authorize the prosecutor to encourage the witnesses not to be interviewed concerning legitimate defense questions bearing on the alleged crime.
Section DR 7-103(B) of Oregon's Code of Professional Responsibility is addressed specifically to prosecutors and requires a prosecutor to “make timely disclosure” to the defense of the existence of any exculpatory evidence. DR 7-109, more generally, forbids any lawyer either to suppress any evidence that either he or his client (in this case, the government) is obliged to reveal or produce, or to “advise or cause a person to secrete himself * * * for the purpose of making him unavailable as a witness.”3 A parallel policy not limited to litigation finds expression in DR 7-102(A)(3).4
We do not imply that the prosecutor in this case violated one of these disciplinary rules. If the issue were professional discipline, the rules would not apply beyond their terms, whatever the underlying policy. See In re Ainsworth, 289 Or 479, 493, 614 P2d 1127 (1980). But this perspective, appropriate when a professional license or reputation is at stake, does not mean that the rules have no underlying policy. Implicit in the rules, as in ORS 135.815, plainly is a policy favorable to access to witnesses and evidence and hostile to improper adversarial interference with such access. In the context of a criminal prosecution, this principle denies the state the right to discourage witnesses from telling the defense what they know.
*541We are mindful that some witnesses may decline to be interviewed by the defense. We do not hold that witnesses may be compelled to speak with the defense counsel prior to trial. Compare United States v. Long, 449 F2d 288, 295-296 (8th Cir 1971), cert den 405 US 974 (1972). We do not hold that the prosecutor must encourage witnesses to consent to being interviewed by defense counsel, or that it is improper for a prosecutor to advise prospective witnesses of their right to refuse to submit to a pre-trial interview by the defense. Compare, United States v. White, 454 F2d 435, 439 (7th Cir 1971), cert den 406 US 962 (1972). We hold that a prosecutor should not improperly interfere with the effort by the defense to interview prospective witnesses by instructing them not to talk to the defense attorney or by telling them that “it would be better if they didn’t say anything.”
Criminal trials should be conducted fairly. Although the system may not always guarantee equal access to relevant evidence, our system certainly should not put a premium upon prosecutorial suppression of access to relevant evidence. The secretion of witnesses is expressly prohibited by DR 7-109, and ORS 135.815 suggests the conclusion that the district attorney not frustrate the defense in the preparation of its case by preventing interview of important witnesses by the attorney for the defendant.
The following statement of the Supreme Court of Pennsylvania, made in a case in which the witness was willing to be interviewed, but only if the district attorney consented, is in point:
“We are aware of no authority in the law which gives the district attorney the right, in general, to deny defense counsel access to the Commonwealth’s witnesses. Under the ethical standards of our profession, in the absence of special circumstances to which we hereinafter allude, the consent of the district attorney should not be necessary to insure defense counsel’s right to interview a witness prior to the trial. The primary duty of a district attorney is not to convict, but to see that justice is done. [Citing DR 7-103(B), DR 7-109(A) and (B).]
u* * * * *
“It has been vigorously urged that there is a substantial difference between affirmatively ordering a witness not to *542talk with defense counsel, and merely advising the witness that the prosecution does not consent to the interview. We are not persuaded. In the majority of instances, as in the case at bar, the effect of the prosecutor’s expressed disapproval would be to prevent defense counsel from speaking with the witness until the witness testifies at trial. This result is unsatisfactory. We are concerned with the interference by a district attorney with the right of a defendant to interview an otherwise willing witness. The issue is not the form which that interference takes, but rather whether it is effective. A district attorney who wishes to bar such an interview may employ one of three methods: he may hide or incarcerate the witness; he may order the witness not to speak; or he may ‘advise’ the witness not to speak. The district attorney certainly has not adopted either of the first two methods. His choice of the third method, even though exercised in good faith, nevertheless was in error.
“We are of the view that, in the absence of an affirmative and convincing showing of exceptional circumstances or compelling reasons, a district attorney may not interfere with the pre-trial interrogation by a defense counsel of persons who may be called upon as witnesses in the case.* * * Unquestionably, we cannot force a district attorney to approve of such questioning; however, we may certainly bar him from communicating his disapproval to the witness. We are not hereby saying that witnesses themselves may be compelled to speak with defense counsel prior to trial. We merely intend to prevent the prosecuting attorney from interfering with this aspect of the defendant’s preparation for trial.” (Emphasis theirs; footnote omitted.) Lewis v. Court of Common Pleas of Lebanon County, 436 Pa 296, 260 A2d 184, 188-189 (1969).5
The state characterizes the defendant’s position as a request that this court declare, “* * * on constitutional grounds, that all criminal defendants be able to interview all the state’s witnesses in every case.” Our holding is not based upon constitutional grounds, nor do we hold that the *543witnesses whom the prosecutor intends to call must be made available for all criminal defendants to interview. As stated above, we only hold that the state cannot order or advise a witness not to speak to the defense attorneys.6
II
The defendant was not prejudiced
Having determined that it is improper for a prosecutor to instruct a witness not to be interviewed by the defense, we consider whether the case must be reversed for violation of that rule. When access to witnesses is impaired by prosecutorial misconduct, the defendant must first take appropriate action to overcome the obstacle sought to be imposed by the prosecutor, if the opportunity exists. For example, if prior to trial the defense attorney becomes aware of improper prosecutorial efforts to prevent interviewing of witnesses, assistance of the court could be requested. Upon discovery of improper prosecutorial conduct which may impede the defendant’s trial preparations or presentation of evidence, if opportunity exists to invoke a remedy which may eradicate the possible prejudice, the defendant must timely act by taking appropriate steps to attempt to cure the problem. Defense attorneys cannot sit on their hands, doing nothing, and later complain of the prosecutor’s misconduct.
In an appropriate case, a recess or postponement might be the proper remedy. See United States v. Cook. 608 F2d 1175, 1181 (9th Cir 1979), cert den, 444 US 1034 (1980). Other courts have granted motions to interview, Mota v. Buchanan, 26 Ariz App 246, 547 P2d 517 (1976), or granted an injunction enjoining the type of conduct here involved. Coppolino v. Helpern, 266 F Supp 930, 936 (SD NY 1967).
*544In Lewis v. Court of Common Pleas of Lebanon County, 436 Pa 296, 260 A2d 184, 186 (1969), the trial court, upon the defendant’s motion, ordered “ * * that the District Attorney is enjoined not to prohibit [the witness] from discussing the testimony and the evidence with counsel for the defendant. * * *” Upon appropriate motion, a trial court might order a prosecutor to withdraw the instructions to the witness. We also take note of ORS 136.080-136.100, which provide for depositions of witnesses as a discretionary condition of requested postponement.7 Here, none of these steps were taken or requested.
Both the store manager and the victim testified that they would not have talked to the defendant’s representatives, in any event. At the post-trial hearing on the defendant’s motion for reconsideration, the trial judge opined that a postponement or recess would have been of no avail to the defense, observing that the witnesses had “strong ideas about the case” and felt “very strongly with respect to this defendant.” The defendant has not pointed us to any evidence that the misconduct had any effect upon the outcome of the case or interfered with her preparation for trial or presentation of a defense. We find nothing in the record which leads us to believe that the prosecutor’s misconduct deprived her of a fair trial. We therefore affirm. Or Const, Art VII (Amended), § 3; ORS 138.230.8
The Court of Appeals stated:
“Though we may not approve of the conduct of the prosecutor, there is no ground for reversal of defendant’s conviction in the absence of a showing of an instruction not to cooperate with the defense which in fact resulted in a refusal to cooperate.” 51 Or App at 160.
We read the Court of Appeals opinion as holding that, even though the conduct may have been improper, there was no prejudice to the defendant.
The thoroughness of the defense attorney’s investigation, including contacting prospective witnesses, may determine the success of the defense effort. See ABA Standards for Criminal Justice at 4.53-55, and Oregon Criminal Law Handbook § 1.5 (1969).
DR 7-109:
“(A) A lawyer shall not suppress any evidence that he or his client has a legal obligation to reveal or produce.
“(B) A lawyer shall not advise or cause a person to secrete himself or to leave the jurisdiction of a tribunal for the purpose of making him unavailable as a witness therein.”
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DR 7-102(A)(3):
“In his representation of a client, a lawyer shall not: “* * * (3) conceal or knowingly fail to disclose that which he is required by law to reveal.”
The quoted material makes reference to “exceptional circumstances” in which the rule would not apply. Situations may arise in which the district attorney can show “exceptional circumstances or compelling reasons” why the defendant’s attorney should not be permitted to interview or contact a prospective witness. Aside from the fact that this is not such a case, it is probable that the district attorney, with appropriate assistance from the trial court, as needed, can fashion an appropriate remedy in such cases. Compare, J. Collins, Discovery in Criminal Cases, contained in The Prosecutor’s Sourcebook, Vol 1, at 377, 383-384 (B. George & I. Cohen ed 1969).
We see no necessity for otherwise extending the discussion on this issue, other than to point out that this holding is consistent with Standard 3-3.1(c) of the ABA Standards for Criminal Justice (1980). It reads:
“(c) A prosecutor should not discourage or obstruct communication between prospective witnesses and defense counsel. It is unprofessional conduct for the prosecutor to advise any person or cause any person to be advised to decline to give to the defense information which such person has the right to give.”
A collection of cases, pro and con, may be found at 90 ALR 3d 1231 (1979). We note that the plaintiff has not cited, and we have found no cases approving the type of prosecutorial conduct here involved.
In citing such cases, we note that procedural statutes vary from jurisdiction to jurisdiction. Procedures invoked in other jurisdictions are not necessarily appropriate under Oregon practice rules.
ORS 138.230 provides:
“After hearing the appeal, the court shall give judgment, without regard to the decision of questions which were in the discretion of the court below or to technical errors, defects or exceptions which do not affect the substantial rights of the parties.”
Defendant cites Chapman v. California, 386 US 18, 24, 87 S Ct 824, 17 L Ed 2d 705 (1967), for the proposition that the state, as the beneficiary of a constitutional error, must “* * * prove beyond a reasonable doubt that the error complained of did not contribute to the verdict obtained.” Our holding is not based upon any “constitutional error.” Even applying the Chapman standard upon which the defendant relies, we are satisfied, beyond any reasonable doubt, that the error complained of did not contribute to the guilty finding.