In the aftermath of a homicide the Office of the Chief Medical Examiner (hereinafter OCME or the "medical examiner”) is required by law to "take charge of the dead body” and "fully investigate” the cause of death (Administrative Code of City of NY § 17-202 [a]). In the course of this investigation the medical examiner must take possession of and deliver to the police objects from the crime scene probative of the way in which the death occurred (ibid.) and may "administer oaths and take affidavits, proofs and examinations” (NY City Charter, ch 22, § 557 [e]). The medical examiner must also perform an autopsy and related examinations (Administrative Code § 17-203; Public Health Law § 4210 [2] [c]) and must "promptly deliver to the appropriate district attorney copies of all records relating to every death as to which there is, in the judgment of the medical examiner in charge, any indication of criminality” (NY City Charter, ch 22, § 557 [g]; emphasis added). Nor is this the end of the medical examiner’s duty to investigate and report, for subsequent to the delivery of the autopsy and other examination records, the medical examiner may be required to supply to the District Attorney or Police Commissioner "such further records, and such daily information, as they may deem necessary” (Administrative Code § 17-205).
From the foregoing it would seem clear that if the medical examiner has complied with his statutory obligations, he will, by the time of any murder trial have forwarded to the appropriate prosecutor all autopsy and other records relating to the victim’s death. It is additionally clear that once these records have been delivered to the prosecutor, the prosecutor will in turn be required, pursuant to statute and well-settled case law, to deliver to the defense any nonconfidential written or recorded statements of prosecution witnesses found in those records relevant to the testimony those witnesses will be called upon to provide (CPL 240.45 [1] [a]; People v Rosario, 9 NY2d 286, cert denied 368 US 866).
An OCME pathologist is, almost invariably, called to testify at the trial of one accused of criminally taking another’s life, the pathologist’s testimony being essential to establish, among other things, the cause, circumstances and time of death and, often, the identity of the perpetrator. Accordingly, effective *115cross-examination of the pathologist will in many cases be vital to the defendant’s prospects for acquittal. We have in this State recognized that "a right sense of justice” requires that as the defendant and his counsel set about the business of cross-examining and attempting to impeach witnesses for the prosecution, they be afforded the "full benefit” of prior recorded statements of those witnesses—at least to the extent that such statements are within the prosecutor’s possession or control (People v Rosario, supra, at 289; People v Poole, 48 NY2d 144, 149; People v Perez, 65 NY2d 154, 158; People v Ranghelle, 69 NY2d 56, 62). And, as should be evident, if the law has been followed by the medical examiner, the prosecutor will indeed have in his or her possession all of the medical examiner’s prior recorded statements respecting the death as to which he or she has been called upon to give evidence at trial. The defendant then has every reason to expect that by the time of cross-examination, if not before (see, CPL 240.45 [1] [a]), he or she will receive from the prosecutor all of those statements. It is in fact only if there has been some failure either by the medical examiner or the prosecutor to comply with the law that a defendant will be deprived of all of the medical examiner’s previous written or recorded statements for use in cross-examination.
In the cases at bar it is clear that the medical examiner did not in fact deliver to the prosecution "all records relating to every death as to which there [was], in the judgment of the medical examiner in charge, any indication of criminality” (NY City Charter § 557 [g]; emphasis added) and that the prosecution, not having received all such records, did not turn over to the defendants all of the medical examiner’s prior recorded statements respecting the homicides of which the defendants were accused and about which the medical examiner would testify as a prosecution witness; in three of the four cases it would appear that audiotape recordings containing the medical examiner’s contemporaneous account of the autopsy performed on the homicide victim were not turned over to the prosecutor and in the remaining case that an autopsy worksheet was omitted from the records delivered by the medical examiner to the prosecutor. The People do not in the main contend that these materials were properly withheld by the medical examiner1 or that, had they been turned over *116to the prosecution, as they should have been, the prosecution would not then have been obliged to make the tapes and worksheet available to the defense for use in cross-examination. It is rather the People’s principal contention that they were not responsible for the disclosure of the subject materials because the materials were never transferred by the medical examiner either to the prosecution or to the police.* 2 According to the People, then, the fault, if there is any, lies entirely with the medical examiner and is not addressable as a Rosario violation.
The People’s assignment of fault, even if correct, does not alter the fact that material which should have passed to defendants as Rosario material did not. Indeed, the irreducible fact is that although the defendants were entitled by law to copies of the autopsy tapes and worksheets, they did not receive them and, accordingly, were unable to use them in cross-examining the OCME pathologists called by the People. While the majority pronounces quite confidently that the subject materials could not possibly have been of value to the defendants, this is a judgment which it may not make. The central and still valid teaching of Rosario (supra, at 289-290) is that it is the function of counsel for the accused, not the court, to assess the utility for defense purposes of prior statements of prosecution witnesses. Accordingly, it is the rule that neither the trial court nor an appellate panel may substitute its assessment of evidentiary utility for that of defense counsel; just as a trial court may not prescreen the prior statements of prosecution witnesses to determine which are appropriate for use in cross-examination (People v Rosario, supra, at 289), neither may an appeals court retrospectively excuse the failure to turn over Rosario material upon the speculation that counsel could not have used the withheld material to his client’s advantage (People v Jones, 70 NY2d 547, 550). All Rosario material must, therefore, be turned over to defense counsel prior to cross-examination and the failure to do so will, subject to certain closely drawn exceptions, result in appellate reversal, even though appellate Judges such as my colleagues on this panel are unable to perceive the failure as *117prejudicial (People v Consolazio, 40 NY2d 446, 454; People v Jones, supra).
There is no question that the present defendants have all been denied the use in cross-examination of material which should have passed to them from the People in satisfaction of the People’s disclosure obligations pursuant to People v Rosario (supra). Upon what ground then are these defendants to be denied the remedy afforded other defendants from whom Rosario material has been withheld? None is offered either by the majority or the People except that the failure to disclose the tapes and worksheet was at its inception the fault of the medical examiner. It can, however, matter not at all to the basic fairness of a murder trial that material to which the defendant was entitled in order effectively to cross-examine the pathologist who investigated the death and performed the autopsy upon the victim, was withheld in the first instance by the medical examiner rather than the prosecutor. Regardless of who was first at fault, the result was to deprive the defense of material it was entitled to receive from the prosecution for use in cross-examination. This was material of a sort whose transfer to the defense prior to cross-examination the courts of this State have deemed categorically essential to a fair trial and there exists no principled basis for denying the within defendants the remedy ordinarily mandated when material which should be disclosed as Rosario material is withheld.
It is precisely to avoid a result as arbitrary and anomalous as that embraced by the majority that the People’s disclosure obligation under Rosario (supra) has been held to extend not merely to material within their actual possession, but in addition to material within their control (People v Perez, supra, at 158-159; People v Ranghelle, supra, at 64). Thus, as here, the People may not claim an exemption from their obligation to disclose material pursuant to Rosario simply because the material did not of its own find its way as it should have into the prosecutor’s files. Where the prior statements of a prosecution witness upon the subject matter of his or her testimony are readily ascertainable by the prosecutor in the ordinary course of preparing his or her case for trial, the statements must be located by the prosecutor and produced to the defendant (see, People v Ranghelle, supra, at 64). Any less demanding rule would seriously compromise society’s interest in maintaining criminal trials as truth-finding processes (supra). This is particularly so respecting disclosure of records generated by the OCME, for while the prosecutor is *118given unfettered access to all OCME records relating to a homicide and, indeed, should actually have all such records promptly delivered to him in accordance with the statute, the defendant charged with the homicide is not afforded comparable access. The defendant, moreover, given the statutory and common-law disclosure obligations of both the medical examiner and the prosecutor, may justifiably rely upon the prosecutor diligently to review the entire OCME file pertinent to a homicide of which he has been accused and deliver all Rosario material found in that file to the defense. If the prosecutor does not insist, as he should in the ordinary course of his prosecutorial duties, upon receiving from OCME all records respecting the death which has become the subject of the prosecution, it may well be that extremely critical material absolutely essential both to the prosecution and to effective cross-examination by the defense, and in either case to the integrity of the trial as a truth-finding exercise, will never be brought to light. It is, in fact, precisely to records such as those generated by OCME that the Rosario disclosure obligation must extend if it is in any real sense to fulfill its purpose of safeguarding the truth-seeking process.
The People, in any case, make no argument demonstrating that they did not have control over all of OCME’s records respecting the homicides for which the defendants were tried, including the autopsy audiotapes and worksheets. Obviously, given the aforecited statutory provision no such argument can be made. Indeed, it is clear that the People have every bit as much control over the homicide records of the medical examiner as they have over forensic records generated by the police laboratory which are indisputably subject to disclosure pursuant to Rosario. Rather, the People argue that OCME is not a police agency and that they have no responsibility to seek out and produce materials found in agencies whose principal institutional mission is not law enforcement. Suffice it to say that the sweeping and completely arbitrary exemption claimed by the People finds no support in case law which consistently extends the People’s disclosure obligation to materials within the People’s control. Doubtless, if it had been the intention of the Court of Appeals to limit the People’s obligation in the manner contended by the People, it would have done so; the claimed limitation is after all relatively easy to express. That the Court of Appeals has not done so is plainly attributable to the circumstance that, as distinguished from the limiting concept of control, the limitation proposed by the *119People has nothing to do with the ends the Rosario disclosure obligation was intended to promote. As noted, far from providing some reasonable assurance as to the integrity of the truth-seeking process, the limitation the People propose will likely impair it. The rule advanced by the People is, in the end, simply one of convenience.
It is, of course, highly disquieting that the combined failure of the People and the medical examiner to avail the defense of OCME material which it should have had, may render infirm not only the convictions at bar but, if the People’s representations are correct, numerous others. It should, however, be at least equally disquieting that a rule of disclosure deemed essential to the fairness of criminal trials has apparently been long and widely disregarded, raising the distinct possibility that numerous persons have been wrongfully convicted and penalized for the commission of most serious crimes.
Accordingly, the orders of the Supreme Court, New York County, entered November 23, 1993 (James J. Leff, J.) (Smith); December 31, 1993 (Daniel P. FitzGerald, J.) (Johnson); November 15, 1993 (Herbert J. Adlerberg, J.) (Railey); and October 13, 1993 (Edwin Torres, J.) (Carpenter), denying the defendants’ CPL 440.10 motions, should be reversed, and the motions granted to the extent of remanding each case for a hearing to determine whether the Rosario materials which were disclosed were the duplicative equivalent of those which were not disclosed.
Ellerin, Wallach and Rubin, JJ., concur with Carro, J.; Murphy, P. J., dissents in a separate opinion.
Orders, Supreme Court, New York County, entered November 23, 1993, December 31, 1993, November 15, 1993, and October 13, 1993, affirmed.
. Although the People do allude to a "policy” of the medical examiner pursuant to which certain materials were not delivered to the prosecution, *116there is no evidence of any such policy before the Court. Moreover, even if there were such a policy it would not be legally sustainable given the governing statute’s clear direction that all the medical examiner’s homicide records be delivered to the appropriate prosecutor.
. It is conceded that if the subject materials had been delivered to the police, the prosecutor would be responsible for their production.