Three defendants were tried in the Suffolk Superior Court on indictments charging each with kidnap *452 ping, with intent to extort money (G. L. c. 265, § 26), making threats with intent to extort money (G. L. c. 265, § 25), assault and battery to collect a loan (G. L. c. 265, § 13C), and assault and battery by means of a dangerous weapon (G. L. c. 265, § 15A). Defendant Charles L. Costa was also charged with knowingly transporting illegal alcoholic beverages (G. L. c. 138, § 22). On the defendants’ motions at the close of the Commonwealth’s case, the trial judge directed verdicts of not guilty as to so much of the kidnapping indictments as charged extortion, on the indictments charging threats to extort, and on the indictments charging assault and battery to collect a loan. The jury found the defendants guilty of kidnapping and assault and battery with a dangerous weapon. Additionally, Costa was found guilty of illegal transportation of alcoholic beverages. The defendants claimed an аppeal pursuant to G. L. c. 278, §§ 33A-33G. We allowed the defendants’ application for direct appellate review.
The defendants claim three grounds on which they believe reversal of their convictions is required. First, they argue that the prosecutor was guilty of prejudicial misconduct by including in his opening statement a summary of the testimony that he expected to elicit from the alleged victim. The basis for this allegation of misconduct is the fact that the alleged victim had, through his counsel, announced in court prior to the prosecutor’s opening statement that he would invoke the constitutional privilege not to incriminate himself and consequently would refuse to testify. Second, the defendants argue that the judge failed adequately to instruct the jury so as to protect the defendants from the prejudicial effect of the prosecutor’s opening statement. Third, the defendants assert that the prosecutor’s action in calling the alleged victim to the stand and compelling him to claim the privilege in the presence of the jury was prejudicial and grounds for reversal.
We find no error, and thus affirm the judgments of the Superior Court.
*453 1. The prosecutor’s opening statement. The alleged victim, and prospectively the Commonwealth’s chief witness, was one Owen J. Roberts, III. Roberts had been in the protective custody of the district attorney’s office from thе time of his appearance before the grand jury on December 3, 1975, until April 20, 1976, when he was ordered held on $100,000 bail with double surety as a material witness. During that period he apparently had been fully cooperative with law enforcement officials. On April 21, at a hearing on a motion by Roberts’s counsel to reduce bail, Roberts’s counsel informed the judge, the prosecutor, and the defense attorneys that his client had decided to “invоke his privilege against self-incrimination as to any events which are alleged to have occurred on November 30, [1975,] which forms the crux of this case.” The prosecutor indicated to the judge that, until that moment, he had believed Roberts “fully intended to cooperate and testify in this case.”
On the first day of the trial, April 26, immediately after the jury had been empanelled, the judge held a hearing out of the presence of the jury. The purpose of the hearing, requested by the attorneys for the defendants, was to inquire (a) whether the prosecutor intended to refer in his opening statement to testimony expected to be elicited from Roberts, and (b) the effect that should be given to the announcement by Roberts’s counsel that his client would invoke the Fifth Amendment to the United States Constitution. The following information wa.s presented to the judge during the course of that hearing;. First, the prosecutor stated that he would tell the jury thaxt they would hear certain testimony tending to establish the .guilt of the defendants. The content of that expected testimony would in fact be based to a significant degree on the testimony of Roberts before the grand jury, although the jury would not be told that Roberts was the prospective witness, nor told how the prosecutor knew what that witness would testify. Second, counsel for the defendants brought to the attention of thе judge Roberts’s stated intention to invoke the Fifth Amendment with regard to the events on the night in question. Third, counsel for the *454 defendants argued that to allow the prosecutor to describe Roberts’s expected testimony would allow prejudicial information to reach the jury. They argued that this would create the impression that Roberts had been threatened and was afraid to testify, an impression that would be strengthened when Roberts actually took the stand and invoked his Fifth Amendment privilege.
After hearing the argument of counsel, the judge refused to grant a motion by the defendants that the prosecutor be ordered not to refer in his opening to the testimony he hoped to elicit from Roberts. The judge did instruct the prosecutor generally that he could include in his opening only such facts as he could “reasonably anticipate” would be admitted in evidence. Counsel for the defendants toоk exception to the judge’s refusal to grant their motion.
The issue raised by the preceding facts is before us on two assignments of error. One assignment of error cites the judge’s actions in allowing the prosecutor to refer in his opening statement to the evidence he expected to introduce through Roberts’s testimony (although he did not identify the testimony as coming from Roberts either by name or as the alleged victim). The other assignment clаims error in the judge’s denial of the defendants’ motion for mistrial, made after the defendants rested, based on the prejudicial impact of the prosecutor’s reference during his opening to facts that were never proved during trial.
“The proper function of an opening is to outline in a general way the nature of the case which the counsel expects to be able to prove or support by evidence.”
Posell
v.
Herscovitz,
The defendants emphasize language in one of our cases that they interpret as establishing a much narrower view of the permissible scope and сontent of a prosecutor’s opening statement. In
Commonwealth
v
Bearse,
*456
Moreover, the failure of the prosecutor to prove the existence of a loan transaction or extortion, and the resulting action of the judge in directing verdicts on the related charges, may well have undercut the jury’s cоnfidence in the prosecutor thereby benefiting, rather than prejudicing, the defendants. We think that the special circumstances of the
Bearse
case do not apply to the facts before us and that the usual standard, recently reiterated in
Commonwealth
v.
Martin, supra,
is applicable. The prosecutor properly could have referred in his opening to anything that he expected to be able to prove by evidence. This expectation must, оf course, have been reasonable and grounded in good faith. See
Gladden
v.
Frazier,
Applying this standard, we cannot say that the prosecutor acted improperly in alluding to the substance of Roberts’s hoped for testimony even though Roberts’s counsel had repeatedly asserted that his client would invoke his Fifth Amendment privilege. As the judge correctly observed during the course of the hearing on the opening statement: “A person can’t refuse to testify simply because he doesn’t care to testify.” See
Commonwealth
v.
Johnson,
2. The judge’s instructions. The defendants argue that the judge was under a duty, which he failed to fulfil, to instruct the jury sua sponte in such a manner as to protect the defendants from the prejudicial effects of the prosecutor’s opening statement. 1 Much of the forсe of this argument is dispelled by our conclusion that the prosecutor’s opening remarks were not improper. Moreover, the judge adequately instructed the jury on the limited purpose and effect of the opening. At the beginning of the prosecutor’s opening, the judge stated that “the Commonwealth’s opening is not evidence, but it is simply an outline of what may be offered in evidence.” The prosecutor repeated this caution during *458 his remarks. The judge repeated it after the opening. At the conclusion of the trial, the judge again referred to the function of the opening in his charge to the jury. He charged that “the Commonwealth, through its lawyer, a district attorney, makes what is called an opening. That is not evidence. That is merely an expression of what, at the time it is made, the district attorney feels and intends to offer as evidence. It is not to be considered by you as evidence, and if indeed statements are made of anticipated proof, and then that anticipated proof does not materialize for any one of several reasons perhaps, then you will not consider adversely to the defendants anything that the district attorney has said in his outline of anticipated proof.”
Based on our review of the transcript, we see no basis for faulting the judge on his handling of the possibly prejudiсial impact on the jury of the prosecutor’s opening statement. His repeated instructions regarding the limited purpose and effect of the opening were timely, clear, and forceful. We do not think that this is a case in which the judge’s instructions are inherently insufficient to remedy the prejudice of improper remarks or inadmissible evidence brought to the attention of the jury. See
Commonwealth
v.
Walker,
3. Calling the witness. After the prosecutor’s opening statement and just before the Commmonwealth was to call Roberts as its first witness, the prosecutor requested a voir dire. The prosecutor told the judge that he felt “compelled to request this voir dire in view of the representations made that this witness [Roberts] will in fact invoke the Fifth Amendment.” The defense attorneys joined in the request. The prosecutor called Roberts to the stand, outside the presence of the jury, and asked him several questions. Roberts was asked, among other things, whether he was in Boston in the early morning hours of November 30, 1975 (the date of the crimes alleged in the indictments), and *459 whether he was in Boston on the evening of November 29. On the advice of counsel, Roberts refused to answer both questions on the ground that the answers might incriminate him. He continued to refuse after being ordered by the judge to answer. The judge then adjourned the voir dire hearing until the next day so as to allow counsel an opportunity to seek appellate review or submit memoranda of law. When the hearing resumed the next day, Roberts was asked the same two questions and again refused to answer on Fifth Amendment grounds. The judge ruled that the answers could not tend to incriminate Roberts and that the Fifth Amendment privilege was inapplicable. Roberts was then adjudged in contempt.
Notwithstanding the results of the voir dire interrogation of Roberts, the prosecutor determined that he would call Roberts to testify before the jury as the Commonwealth’s first witness. This decision was made despite the strenuous objections of defense counsel. The judge ruled that Roberts could be called, to which the defendants properly took exception. The prosecutor’s position was that he had “a right and a duty” to call Roberts, at leаst to the extent that the inquiry was limited to the two questions as to which the judge had already ruled the Fifth Amendment to be inapplicable. Roberts was called to the stand by the prosecutor, asked the same two questions, and ordered to answer by the judge. After invoking the Fifth Amendment, the witness was excused. The judge then instructed the jury that Roberts’s refusal to answer the two questions could not be considered against the defendants, that the refusal and the judge’s orders to answer were not evidence, and that no inferences adverse to the defendants were to be drawn from the exchange.
The defendants assign as error the judge’s decision to allow the prosecutor to call Roberts as a witness after he had been held in contempt during the voir dire hearing.
2
Our
*460
recent decision in
Commonwealth
v.
Martin,
*461 The record in this case shows no imрroper purpose on the part of the prosecutor. The recalcitrant witness was the alleged victim, not an accomplice or alleged coparticipant in the crime, nor was there any indication of association with the defendants in other possibly illegal ventures. Also, a ruling that the privilege was improperly claimed had been made. The prosecutor was entitled to make an effort to gain the witness’s testimony in this circumstance.
Once Roberts was called to the stand the “questioning was not insistent or extended, nor did it suggest particularized states of fact from which the jury might the more easily draw harmful inferences.” Commonwealth v. Martin, supra at 421. The two questions put to Roberts before the jury were not “fact laden.” To the contrary, they were so innocuous on the surface as to lead the judge to conclude that their answers could not possibly tend to incriminate Roberts.
Wе do not believe that the defendants were prejudiced by the prosecutor’s action. This conclusion is based on the brevity of the questioning, the harmlessness of the questions, and the promptness and forcefulness of the judge’s instructions. Cf.
Frazier
v.
Cupp,
The impression made on the jurors by Roberts’s invocation of the Fifth Amendment did not add the “critical weight” that brought about the verdicts of guilty. Commonwealth v. Martin, supra at 413-414, and cases cited. Nor do *462 we think that the action of the prosecutor satisfied the Martin formulation of professional misconduct of the type that might justify reversal — that is, the “questioning of a material witness in order to provoke a claim of privilege with a deliberate design to raise those improper inferences in the minds of the jury.” Id. at 414. There apparently was no clear precedent at the time that would have revealed to the prosecutor whether the potential prejudice to the defendants of a contemptuous claim of Fifth Amendment privilege outweighed the value of determining whether the witness would actually invoke the privilege and refuse to testify before the jury. The prosecutor believed in good faith that the balance favored the calling of the witness before the jury. In the circumstances, his judgment cannot be equated with a deliberate design to raise improper inferences.
4. Finding no error sufficient to require reversal, we affirm the judgments of the Superior Court.
Judgments affirmed.
Notes
We discuss the defendants’ contentions as to the adequacy of the judge’s instructions despite the lack of any assignment of error addressed specifically to the judge’s actions in this regard. The general import of the defendants’ arguments fairly may be said to be encompassed in the assignment of error grounded on the denial of the defendants’ motions for mistrial. Those motions, made after the defendants rested, were based on the alleged prejudicial impact of the prosecutor’s reference during his opening to facts that were never proved during trial. In view of the judge’s conscientious effort to place the opening remarks in their proper perspective, see text,
infra,
we do not believe that the judge abused his discretion in denying the motions for mistrial. See
Commonwealth
v.
Gouveia,
The defendants also contend that it was error to order Roberts to answer the questions. We do not think thаt the validity or invalidity of
*460
Roberts’s Fifth Amendment claim in any way affects the defendants’ claim of error. We therefore do not discuss this issue. Cf.
Commonwealth
v.
Turner,
“When a witness in a criminal case refuses to answer questions on the ground of self-incrimination, lay triers may readily, although improperly, make invidious inferences associating the witness with the defendant in an illegal enterprise; and the prejudice to the defendant may be especially hard to remove because he cannot cross-examine the witness as to ‘testimony’ which is in the form of a kind of riddling silence” (footnotes omitted).
Commonwealth
v.
Martin, supra
at 413-414. We note that the claim of the witness, Roberts, of the privilege against self-incrimination would be most unlikely to create an “invidious inference” of association with the defendant in an illegal enterprise as might have been an issue in
Martin.
The witness, Roberts, was the alleged victim; the witness in
Martin
was a coparticipant who had pleaded guilty earlier. The defendants cite
Commonwealth
v.
DuVal,