¶1(dissenting). I do not agree that the erroneous exclusion of the defendant’s proffered rehabilitation testimony was nonprejudicial, nor do I agree that the evidence of the defendant’s prior misconduct was admissible. I would reverse the judgments and remand the case for a new trial of both indictments.
¶2The defendant offered to explain to the jury that the reason he had lied to the police was not self-interest but rather his desire to protect the complainant and her friends from being discovered to be cocaine users. The court recognizes that the defendant “had a right to explain why he lied to the police” (ante at 222), but concludes “with fair assurance” that the exclusion of that evidence was harmless because, even if the jury had believed the defendant’s explanation, they would have found him guilty on the drugging and rape charges anyway (ante at 223). The court’s assurance is unjustified.
¶3The defendant’s only realistic hope of acquittal depended on the jury’s not being satisfied beyond a reasonable doubt that he had had intercourse with the complainant. Unless he had intercourse, it is unlikely that he administered the drugs to enable him to do so. See note 11, supra. The complainant testified that the defendant had had intercourse with her. The defendant testified that he had not. The defendant’s credibility, therefore, was critical to the outcome of the case. The fact, brought out on cross-examination of the defendant, that he had lied to the police investigators, suggested with considerable force that (1) when he spoke to the police, the defendant was conscious of his guilt; human experience teaches that the guilty tend to lie to investigators about both important and unimportant details of the incident under investigation, and (2) the defendant was not a reliable witness because he was not averse to lying “to save his own skin.” Surely, it cannot rightly be said that the portrayal of the defendant as a deceitful man, conscious of his guilt, did not prejudice him. That portrayal, effectively accomplished on cross-examination, cried out for the defendant’s rehabilitation. See Commonwealth v. Errington, 390 Mass. 875, 879-881 (1984). The defendant’s legitimate attempt at rehabilitation was thwarted however. He was not permitted *234to explain to the jury that he had lied, not to protect himself, and not because he had a guilty frame of mind, but to protect others.
¶4In order to find the defendant guilty as charged, the jury had to believe the complainant’s testimony and disbelieve that of the defendant. No one can say with fair assurance that, in choosing whom to believe, the jury was not influenced by the defendant’s cross-examination unmet by any explanation, or that, had they heard the explanation, they would not have arrived at a different verdict. The error cannot properly be considered harmless. Therefore, a new trial on both charges is required.
¶5A new trial on both charges is also required because evidence of the defendant’s earlier conduct with L.J. and K.H. was erroneously admitted on the drugging charge over the defendant’s objection. That error prejudiced the defendant with respect to both indictments. As the court observes (ante at 224), “[i]t is well settled that the prosecution may not introduce evidence that a defendant previously has misbehaved, indictably or not, for the purposes of showing his bad character or propensity to commit the crime charged, but such evidence may be admissible if relevant for some other purpose.” The rationale for this rule is that while such evidence may be marginally probative, “there is the danger that, because a defendant appears to be a bad man capable of, and likely to commit, such a crime as that charged, a jury might be led to dispense with proof beyond a reasonable doubt that he did-actually commit the crime charged. Moreover, it is not fair that a defendant in the course of a trial should be called upon to defend himself against accusations not set forth in the indictment.” Commonwealth v. Stone, 321 Mass. 471, 473 (1947). See McCormick, Evidence § 188 (2d ed. 1972). If this well-settled rule of fairness is to continue to have any vitality whatsoever, the other bad acts evidence in this case must be held inadmissible. The only function of the evidence was to show that the defendant had a general propensity to drug women in order to enable him to have intercourse with them, and that therefore he drugged the complainant for that purpose as charged. That is precisely what the rule prohibits.
¶6*235The court reasons (ante at 227) that the evidence of the defendant’s prior conduct with L.J. and K.H. was “highly probative” in that it showed a distinctive pattern of conduct bearing on the defendant’s state of mind when administering the drug, thus tending to rebut the defense of innocent, therapeutic intent and making more probable the existence of the requisite illegal intent. In support of that contention, the court cites Commonwealth v. Fleury-Ehrhart, 20 Mass. App. Ct. 429, 431 (1985), and cases from other jurisdictions. In all the cited cases, the admission of other crime evidence was affirmed on appeal, not on the ground that the evidence demonstrated a distinctive pattern of conduct (modus operandi), but on the quite different ground that it demonstrated the defendant’s involvement in a common scheme, design, or plan. See Commonwealth v. Gallison, 383 Mass. 659, 673 (1981); Commonwealth v. Schoening, 379 Mass. 234, 242 (1979). Therefore it is difficult to know whether the court approves the admission of the “other crime” evidence in this case because it demonstrates a distinctive modus operandi or a common scheme. In any event, neither theory justifies the admission of the contested evidence.
¶7When a crime has been committed in a unique way, and the person charged with committing the crime has been shown to have had an opportunity to commit it, evidence that the defendant previously committed the same crime in the same unique way has a strong tendency to show that he, and not someone else, committed the crime with which he is charged. The evidence is admissible, therefore, to establish the identity of the assailant. Commonwealth v. Lacy, 371 Mass. 363, 366 (1976). Modus operandi evidence is designed to identify the perpetrator of a crime proven by other evidence. In this case, the question is whether a crime was committed, not who committed it, and therefore the distinctive modus operandi theory does not apply. The court cites no case from Massachusetts or elsewhere holding in a criminal case that evidence of the unusual manner in which a defendant has executed a crime or crimes in the past is admissible to prove that on a particular occasion he possessed criminal intent.
¶8*236Neither does the “common scheme” theory apply. This court said in Commonwealth v. Stone, supra at 473-474, that “[i]n trials of indictments for larceny by obtaining money or property by false pretenses it has been held, as bearing on the defendant’s intent, that his criminal conduct on another occasion is admissible, provided it is reasonably near in time and so connected with the crime charged in the indictment as to show unity of plot and design and that it was part of a common plan or scheme to defraud.” In that case, and in Commonwealth v. Schoening, supra at 242-243, which involved indictments for conspiracy to bribe a public official and conspiracy to steal from the Commonwealth, evidence of other bad acts was held admissible to prove the defendant’s state of mind when those other acts were part and parcel of one ongoing course of conduct. However, the act in question here, together with the two prior acts involving L.J. and K.H. more than two years earlier, cannot be considered phases of one continuous operation if we are to retain the salutary rule requiring the exclusion of evidence of other bad acts to show a defendant’s criminal propensities.
¶9I recognize that in Commonwealth v. King, 387 Mass. 464, 469-472 (1982), this court held that at the trial of an indictment for unlawful, unnatural sexual intercourse with a child under sixteen years of age, the judge properly admitted evidence that during the period of the alleged misconduct the defendant also engaged in sexual acts with the victim’s younger brother. For the first time, this court in Kingapplied the common scheme theory in an action charging a sexual offense. Also for the first time, this court in Kingapplied the common scheme theory, not just to prove the defendant’s state of mind, but to prove that he committed the act with which he was charged. Id. at 478 (O’Connor, J., dissenting). I continue to believe that Kingwas wrongly decided. It is not necessary, however, that I urge the overruling of Kingin support of my contention that the evidence of other bad acts in this case should be held inadmissible. The King case and this one are readily distinguishable.
¶10*237In King, the court concluded that the acts alleged in the indictment and the other acts “formed a ‘temporal and schematic nexus’” because they were committed against a sister and a brother who made their home with the defendant, and the offenses not included in the indictment occurred within the same time period as the offenses with which the defendant was charged. Id. at 472. In the present case, however, the other two acts were with unrelated people, and they occurred six months apart and more than two years earlier than the charged offense.
¶11In King, the court did not purport to overrule Commonwealth v. Welcome, 348 Mass. 68 (1964). In fact, in Commonwealth v. Sylvester, 388 Mass. 749, 757 (1983), the court expressly stated that “Commonwealth v. King, supra,and Commonwealth v. Gallison, [383 Mass. 659 (1981)], do not overrule Commonwealth v. Welcome, supra.”No principled distinction can be made between this case and Commonwealth v. Welcome. In that case, we held inadmissible in a trial for indecent assault and battery on a child under fourteen evidence that the defendant had assaulted other young girls. Id. at 70-71. We “invokefd] the rule that evidence of a distinct crime unconnected with that for which the defendant is indicted cannot be received.” Id.See also Commonwealth v. Ellis, 321 Mass. 669, 670 (1947) (holding that it was error to admit in a statutory rape trial evidence that the defendant molested an older sister). The court makes no effort to distinguish the present case from Commonwealth v. Welcome, supra,or Commonwealth v. Ellis, supra.Rather, the court ignores those cases and turns to foreign jurisdictions for guidance. Commonwealth v. Welcome, supra,articulates good law, and has recently been characterized by the court as stating the current law. That case, and the sound principle of fairness that it enunciates, should not be overruled without discussion adequate to justify such action.
¶12The evidence of the defendant’s earlier conduct with L.J. and K.H. was probative, though not, as the court says, “highly probative” on the question whether the defendant injected Valium into the complainant to enable him to have intercourse with her or for therapeutic reasons. To infer criminal intent, *238however, the fact finder must first infer from the defendant’s prior conduct that he had a propensity to commit that crime, and then to say that a man with that propensity probably had the intent required for the crime charged. Thus, the evidence of prior bad acts was introduced for the purpose of showing his propensity to commit the crime. But “[i]t is well settled that the prosecution may not introduce evidence that a defendant previously has misbehaved, indictably or not, for the purpose of showing his bad character or propensity to commit the crime charged.” The court purports to acknowledge this. See ante at 224.
¶13This court’s decision in Commonwealth v. King, supra,and now in this case, displays a sharp retrogression in its sensitivity to the unfairness of admitting in a criminal case evidence of a defendant’s prior bad acts that was earlier expressed so well in Commonwealth v. Stone, supra, Commonwealth v. Ellis, supra,and Commonwealth v. Welcome, supra.It is difficult, nay impossible, to reconcile that unenlightened trend with the court’s recent progressive recognition of the danger of unfair prejudice inherent in admitting evidence of a defendant’s conviction under G. L. c. 233, § 21, to impeach his credibility as a witness. See Commonwealth v. Elliot, 393 Mass. 824, 832-834 (1985); Commonwealth v. Maguire, 392 Mass. 466, 470 (1984); Commonwealth v. Chase, 372 Mass. 736, 750 (1977). In those cases, we recognized that the greater the similarity between the charged offense and past offenses, the greater the potential for unfairness — even if, unlike here, the jury is instructed that they are to consider the evidence of past bad acts solely on the issue of the defendant’s credibility as a witness. The court is moving in two diametrically opposite directions simultaneously. The direction taken by the court in this case is the wrong one.
¶14The judge instructed the jury that they should consider the contested evidence only with respect to the drugging charge. Clearly, the evidence, erroneously admitted, was prejudicial to the defendant with respect to that indictment. It was equally prejudicial as to the rape indictment despite the judge’s limiting instruction. Commonwealth v. DiMarzo, 364 Mass. 669, 681-*239682 (1974) (Hennessey, J., concurring) (“It is reasonable for us to be confident that in most cases limiting instructions accomplish their intended purpose. Nevertheless, in cases . . . where the evidence subject to limitations has an extremely high potential for unfair prejudice, we have a duty to be skeptical as to the effectiveness of limiting instructions. . . . The reasoning of the [Bruton v. United States, 391 U.S. 123 (1968)] case is highly relevant . . . since that case recognized the futility, even the absurdity, of expecting a jury in some circumstances to conform to limiting instructions”).
¶15Both convictions are flawed by prejudicial error, both in the exclusion of rehabilitative evidence to which the defendant was entitled, and the admission of evidence of the defendant’s prior misconduct. The judgments should be reversed and the case should be remanded to the Superior Court for retrial.