(dissenting, with whom Abrams, J., joins). In a case riddled with deceit and fraud by law enforcement authorities, the court, ignoring the realities of the meaning of a fair trial, contents itself by reciting indignant, but toothless rhetoric. The court describes the conduct of those who would put the defendant on trial and who hold the cards against him as “perfidious,” “contemptible,” “disgusting,” “criminal,” and “in blatant violation of their sworn duties,” yet denies the defendant an effective remedy. Without the ultimate sanction of dismissal with prejudice, this court fails “to discourage government agents from such deliberate and insidious attempts *589to subvert the defendant’s right to a fair trial.” Commonwealth v. Jackson, 391 Mass. 749, 754 (1984).
The prosecutorial team’s “egregious, deliberate, and intentional” misconduct far exceeds that required to establish presumptive prejudice. Commonwealth v. Cronk, 396 Mass. 194, 199 (1985). “[T]he officers’ misconduct was so pervasive as to preclude any confident assumption that proceedings at. . . trial would be free of the taint.” Commonwealth v. Manning, 373 Mass. 438, 444 (1977). Sadly, these proceedings have been poisoned beyond cure solely by the agents of the Commonwealth. Truth and falsehood have become so obscured in this case, at the instigation of the prosecutorial team, that it is impossible to believe that the defendant will be able to obtain a fair trial.1 See Commonwealth v. Lam Hue To, 391 Mass. *590301, 312-313 (1984). The court should not turn a blind eye to the serious degradation of the truth-seeking process, in the hopes that somehow a jury will be able to sort out the whole mess.21 “see no place in due process law for positioning the jury to weed out the seeds of untruth planted by the government.” United States v. Waterman, 732 F.2d 1527, 1532 (8th Cir. 1984), cert. denied, 471 U.S. 1065 (1985).
The court today, in its newfound role as fact finder, substitutes its view of events for that of the judge, riding roughshod over accepted standards of appellate review. There is considerable evidence to support the judge’s finding of fact that there is an undisclosed exculpatory witness. The police have shown that they will do everything within their power to ensure the conviction of the defendant. They failed for months to disclose the existence of informant X. The officers have never offered any explanation for this delay, nor would revelation of X have contradicted any previous sworn statements. In fact, despite the judge’s disclosure order, the police officers never voluntarily revealed the information. Even after dismissal, when the police supposedly “came clean,” they presented two alleged informants — whom they had purportedly been withholding for almost a year — whose testimony the motion judge found to be unworthy of belief. Yet now the court would have us believe that witnesses who have repeatedly misled the court finally are telling the truth, and that they no longer have an incentive to lie. This is sheer nonsense. The very fact that the police officers have already put themselves at personal risk increases their incentive to say anything that would get the defendant convicted. They now have every reason to conceal an exculpatory witness: revealing him now would make their misguided sacrifice of the truth and the Constitution all for naught.
*591At any rate, these considerations regarding credibility should all properly remain within the province of the lower court. See Commonwealth v. Hine, 393 Mass. 564, 568 (1984). The judge below saw these police officers testify in prior proceedings. He, not this court, should determine whether their belated recantation is to be believed. Commonwealth v. Carballo, 9 Mass. App. Ct. 57, 60, S.C., 381 Mass. 227 (1980). Commonwealth v. Grace, 397 Mass. 303, 310-311 (1986). The court today boldly substitutes its own judgment as to credibility for that of the judge, claiming that it is incredible that the informant John could have provided information which led to applications for over thirty search warrants.3
In addition, the court takes great pains to reconstruct a scenario in which the informant John did not necessarily exist. For instance, the court makes much of the fact that a person outside the apartment could tell that the door had been rebuilt. But this type of analysis misconstrues the role of appellate courts. Although we may have found the facts differently, we may not substitute our judgment for that of the motion judge. “We have often stated that ‘ [t]he determination of the weight and credibility of the testimony is the function and responsibility of the judge who saw and heard the witnesses, and not of this court.’ ” Commonwealth v. Hine, supra at 568. Commonwealth v. Moon, 380 Mass. 751, 756 (1980). The judge had before him sufficient evidence to warrant a finding that John exists.4
The court, in its rush to send the defendant to trial, brushes aside well-established principles against relitigation of facts *592after final judgments.5 This court has said, with regard to defendants in criminal cases, “[t]he defendant may not, after losing on one theory, retry his case on an alternate theory on which admissible, highly relevant evidence was available to him át the time of the trial.” Commonwealth v. Freiberg, ante 282, 288 (1989). Apparently, a different standard applies to the Commonwealth. This is not a rule of law; it is a sleight of hand, and a slight to the defendant’s right to a fair trial.
This case has undermined the public’s faith in the administration of justice in this Commonwealth. The court today has done nothing to restore confidence in our now sullied system of justice.6 The saddest aspect of this entire sordid saga of police misconduct may well be that the death of a police officer will go unavenged. Let it be known that the cause of such an event is not the court but the police themselves.
I take exception to the court’s willingness to exonerate the prosecutor by characterizing his strong suspicions of wrongdoing as “an inkling of doubt about the correctness of [his] position.” Ante at 578. While the prosecutor did not create the initial problems, as early as October, 1988, after “an intensive unsuccessful search for the informant [he] began to become convinced that either the informant did not exist or that the police were choosing not to produce him because he would contradict them.” The prosecutor’s suspicions were such that in December, 1988, January, and February, 1989, he “implor[ed] each police officer to call [him] anonymously and give [him] the answer either he does not exist or he does and this is his identity.” Said the prosecutor in his affidavit: “Throughout this same December, 1988, to February, 1989 period, I continued over and over to try to impress Sergeant Amate and Detective Luna that if my suspicions were accurate they should tell the truth.” All the while, the prosecutor mentioned none of this to the judge. Indeed, the prosecutor went so far as to submit a proposed finding of fact which recited that Luna’s “failure to find John ... is not a bad faith failure.” Only when the indictments were dismissed — indeed, on the very day that the indictments were dismissed — did the prosecutor disclose to the judge the misconduct committed by the police officers. Such conduct appears to fall below the standards set by our rules of professional responsibility. See S.J.C. Rule 3:07, DR 7-103 (B), as appearing in 382 Mass. 784 (1982): “A public prosecutor ... in criminal litigation shall make timely disclosure to counsel for the defendant ... of the existence of evidence, known to the prosecutor . . . that tends to negate the guilt of the accused.” See S.J.C. Rule 3:08, PF 7, and PF 12, as appearing in 382 Mass. 797 (1982). Standard PF 12, provides in part: “It is unprofessional conduct for a prosecutor [to] . . . fail to seek withdrawal [of false evidence] promptly upon discovery of its falsity” (emphasis supplied).
Apparently, the court is willing to perpetrate a fraud on the jury. It will allow the defendant to. introduce the statements about John and Stevie which the court insists are false, and will bar the Commonwealth from rebutting that evidence. Under the court’s analysis, the result will give the jury the false impression that John does exist.
I doubt the court would rule in a later case that an affidavit which relies on an informant who supplied information which led to thirty warrants is invalid on its face.
The court unfairly mischaracterizes an isolated statement of the judge, characterizing it as an “initial determination.” The judge stated: “[I]n the quest for the non-existent John, public funds were needlessly expended.” The Commonwealth claimed that John did not exist. Yet the police officers submitted detailed reports and received overtime compensation during the search for someone they now represent as nonexistent. The judge’s sarcastic statement regarding this reprehensible activity was far from a “finding” that John was nonexistent.
The court disregards the procedural posture of the case, choosing to view the Commonwealth’s appeal on the entire record. For the controversial proposition that this court may view the case on the whole record and not solely with respect to the motion for reconsideration the court cites Commonwealth v. McLaughlin, 364 Mass. 211, 229 (1973). That case is no authority for the court’s proposition. McLaughlin stands for the uncontroversial proposition that a trial judge’s rulings of law may be reviewed by appellate courts. That case says nothing about relitigation and review of factual determinations.
I think it appropriate to note the careful, thorough, and conscientious treatment with which the judge in this case handled this particularly difficult and sensitive matter. He has shown courage; we would have done well to follow his example.