The defendant appeals from the judgment of conviction, rendered after a jury trial, of aiding and abetting the sale of narcotics in violation of General Statutes §§ 21a-278 (b) and 53a-8. He claims that the trial court improperly (1) refused to strike the entire testimony of the state’s key witness pursuant to Practice Book § 755 and General Statutes § 54-86b,1 (2) determined that the prosecutor struck the first two minority jurors for neutral reasons, and then refused to seat those two jurors when it later determined that the prosecutor engaged in purposeful discrimination, and (3) determined that the mitigating factors submitted by the defendant could not constitute a significant impairment of mental capacity pursuant to § 21a-278 (b). We reverse the judgment of the trial court and remand for a new trial.2
The jury could reasonably have found the following facts. On January 6,1988, the New Haven police street crime narcotics task force conducted an undercover narcotics operation in the Hill section of New Haven. *306Officer Frank Roberts, a member of the task force, was assigned to make undercover narcotics purchases from dealers on the street. Two surveillance teams were assigned as backups to Roberts, one of which included Officer Joseph Pettola.
By approximately 12:15 p.m., Roberts had been driving around the Hill area for nearly two hours, and had already made several undercover narcotics purchases. Pettola and his partner were parked at the intersection of Sylvan Avenue and Ward Street. At that time, Roberts stopped his car at the intersection of Elliot Street and Sylvan Avenue for approximately five to seven seconds. He saw two persons begin walking up Sylvan Avenue toward his car and one of them was waving his arms at Roberts. Roberts noted at the time that both individuals were black and were wearing beige jackets. Roberts then drove around the block so as to proceed to the intersection of Sylvan Avenue and Asylum Street where he had seen the two men, which was one block away from Pettola’s surveillance position.
When Roberts reached the intersection, he saw two black men standing on the corner, and he pulled his car over to the curb next to them. The first black male approached Roberts and asked him what he wanted. Roberts replied, “I will take one twenty cent piece.” The first male asked, “just one?” Roberts replied affirmatively to the question, and the first male then yelled and gestured to the second male to get “one piece.” The second male then walked down Asylum Street to a tree, reached down and retrieved a small, yellow glassine envelope from a brown paper bag. The second male then proceeded to Roberts’ car with the envelope. While the second male dealt with Roberts, the first male moved away from the car and looked up and down Sylvan Avenue. Roberts handed the second male twenty dollars, took possession of the envelope, and *307drove away. The entire transaction lasted no more than one minute, and Pettola and his partner witnessed the entire transaction from their vantage point.
As Roberts drove away from the scene, he made written notes containing general descriptions of the two men, including their height, weight, clothing description, outstanding marks, age and skin color. Immediately thereafter, he radioed Pettola and gave him a description of the two men. Roberts described them as one wearing a knit hat with “Mercedes-Benz” written on it and the other wearing a similar hat with “BMW” on it. Pettola and his partner remained in surveillance of the two men, who did not leave the area. After waiting long enough so as not to disclose Roberts’ cover, Pettola and his partner drove up the street to the two men and exited their car. They identified themselves as police officers and asked the two men for identification. Pettola recognized one of the men as Darryl Spears, and the other man, the defendant, produced a picture identification card and stated that his name was Roy Jones. Jones gave them his social security number and his home address, 74 Asylum Street.
Pettola and his partner left the scene without making an arrest or retrieving the alleged bag of narcotics near the tree. Later that same day, Pettola and Roberts met at the police station, where Roberts gave the yellow envelope to Pettola, who was to have it tested to determine if it contained a narcotic substance. While at the station, Pettola conducted a search of New Haven police department records for any information about Jones and Spears. The search indicated that Jones had previously been arrested for disorderly conduct, criminal mischief and breach of the peace.
On January 6, the same day that he gave the envelope for testing to Pettola, Roberts proceeded to dictate a police report, using his notes to refresh his *308recollection concerning the chain of events earlier in the day. When the dictation was completed, he gave it to a secretary for transcription. On January 29,1988, twenty-three days after Roberts made the dictation, the typist returned the typed report to Roberts, along with the dictation tape. The typed report indicated the heights for both Jones and Spears as “6'.” Roberts testified that when he read the typed report on January 29, he noticed two mistakes in it, which he had confirmed by checking his field notes from January 6. Roberts then crossed out both typewritten heights, and handwrote “5'10"” as the height for Jones and “5'9"” as the height for Spears. Roberts initialed both cross-outs. Roberts then signed the typed report, dating it January 6, 1988, the date he had dictated it. Roberts testified that he had dictated “5'10"” and “5'9"” as the heights for Jones and Spears, respectively, but that the typist must have incorrectly heard “6'” in both instances. Roberts also admitted that the typed report contained biographical information about Jones and Spears of which he had no knowledge at the time he wrote his field notes.
The defendant was arrested on February 26, 1988. Roberts testified that after the arrest he threw away his notes because the sting operation had been completed. He also testified that, pursuant to department policy, the tape was erased so that it could be used for other dictation.
At trial, the state’s only witnesses were Roberts, Pettola and a toxicologist who testified that the yellow envelope contained cocaine. Upon the completion of Roberts’ direct testimony, the defendant moved, pursuant to Practice Book § 752, for production of all statements made by Roberts concerning this incident that the state had in its possession. The state gave the defendant a copy of Roberts’ typewritten police report with Roberts’ handwritten changes. When the state *309failed to produce either Roberts’ dictation tape or his field notes from January 6, the defendant moved, pursuant to Practice Book § 755, to have Roberts’ entire testimony stricken. After hearing argument by counsel outside the presence of the jury, the trial court determined that it would strike only the in-court identification made by Roberts. The defendant objected to this sanction. Thereafter, without withdrawing his objection to the court’s failure to strike Roberts’ entire testimony, the defendant requested that since the court refused to strike all of Roberts’ testimony, the court should prohibit all of the other state’s witnesses from making in-court identifications of Jones, and should give an adverse inference instruction when it charged the jury. The trial court ruled that it would prohibit all of the other state’s witnesses from making in-court identifications of the defendant. It reserved decision, however, on the defendant’s request for an adverse inference instruction until it was time to instruct the jury. Subsequently, the trial court declined to give the instruction requested by the defendant, and he was convicted as charged.
The defendant claims that the trial court improperly refused to strike Roberts’ entire testimony. He claims that Practice Book § 755 and General Statutes § 54-86b require that a state’s witness’ entire testimony be stricken when the court determines that the state’s failure to produce “statements” is harmful. The state concedes that the dictation tape is a “statement” for purposes of Practice Book § 749.3 The state argues, however, that the defendant was not harmed by the *310destruction and nonproduction of the tape, and thus urges our affirmance of the defendant’s conviction.
Whereas the facts of this case necessitate this court’s return, yet again, to the New Haven police department’s policy of destruction of taped statements, we do so this time in a slightly different setting. Typically, we are presented with a case in which the trial court has found that the state satisfied its burden of proving harmlessness, and thus we must decide whether the trial court abused its discretion in making that finding. Here, however, the trial court has already determined that (1) the dictation tape contained a “statement” for the purpose of Practice Book § 749 et seq., (2) that the New Haven police destroyed the tape intentionally, although not maliciously or with the intent to deprive the defendant of the evidence contained therein, and (3) that the state failed to meet its burden of proving that the destruction of the tape was harmless beyond a reasonable doubt.4 On the basis of those findings, the trial court precluded the other state’s witnesses from the New Haven police depart*311ment from making in-court identifications of the defendant, but it declined the defendant’s request to give an adverse inference instruction.
It has been recognized that the failure to provide material to which the defendant is entitled under Practice Book § 752 et seq. “ ‘may adversely affect a defendant’s ability to cross-examine government witnesses and thereby infringe upon his constitutional right of confrontation.’ ” State v. Williamson, 212 Conn. 6, 20, 562 A.2d 470 (1989). “In such a case, a court would be warranted in strictly applying the harmless error doctrine to require the state to prove harmlessness beyond a reasonable doubt.” State v. Belle, 215 Conn. 257, 269, 576 A.2d 139 (1990). Here, although the trial court did not expressly find that the nonproduction of the tape infringed upon the defendant’s right of confrontation, we believe that such a finding is supported by the record.
“In determining the effect of the state’s nonproduction on a defendant’s opportunity to cross-examine, we have considered such factors as the trial or reviewing court’s access to the unproduced material, the declarant’s adoption of a counterpart transcript within a short time after making the statement, and the extent to which the defendant’s conviction rested on the testimony of the witness whose pretrial statement had been destroyed.” Id., 269-70. In this case, neither we nor the trial court had access to the unproduced material. *312Roberts’ adoption of a “counterpart” transcript was made twenty-three days after he dictated his report, during which time he had ample opportunity to check department records for the accuracy of his report. Additionally, Roberts did not “adopt” the entire counterpart transcript, as evidenced by the two changes regarding the heights of the suspects he made on the typewritten report. Finally, the defendant’s conviction rested largely on the testimony of Roberts, who was the only witness who testified regarding the details of the alleged drug deal, and without whose testimony the state would not be able to establish a complete chain of custody concerning the narcotics he allegedly purchased from the defendant and his partner. The trial court, therefore, properly required the state to prove that the destruction of the tape was harmless beyond a reasonable doubt.
The state does not challenge the findings of the trial court as incorrect but appears to base its argument on the premise that the court never made these findings. It is the position of the state that the failure of the trial court to give an adverse inference charge should be interpreted as a finding that the nonproduction of the tape was harmless. A thorough examination of the record leads us to conclude that the findings were in fact made by the trial court, which conclusion is further evidenced by the fact that the trial court imposed sanctions by precluding in-court identifications of the defendant by the New Haven police officers involved in this matter. The state may not now challenge these findings of the trial court as they have failed to raise such a challenge properly.5
*313The narrow issue with which we are presented, therefore, is whether the trial court was required, pursuant to Practice Book § 755 and General Statutes § 54-86b, to strike a state’s witness’ entire testimony when the trial court has found that the state’s failure to produce § 749 pretrial statements of the particular witness harmed the defendant. “The appropriate sanctions for the state’s failure to comply with discovery are set forth in Practice Book § 755. That section requires the trial court either to strike the testimony of the state’s witness or ‘upon motion of the defendant’ to declare a mistrial if ‘the interests of justice require.’ ” State v. Silva, 201 Conn. 244, 251, 513 A.2d 1202 (1986). In State v. Williamson, supra, 28, the court held that because the defendant was harmed by the destruction of the statement, the Appellate Court properly concluded that the trial court abused its discretion in not striking the entire testimony of the witness whose statement had been destroyed. In In re Jesus C., 21 Conn. App. 645, 652, 575 A.2d 1031 (1990), we held that where the state failed to prove the harmlessness of the nonproduction of the statements of two particular witnesses, the trial court abused its discretion by not striking the entire testimony of those two witnesses. Here, the trial court abused its discretion by failing to strike Roberts’ entire testimony after it had concluded that the destruction of the tape of Roberts’ statement harmed the defendant.
We find unpersuasive the state’s argument that the jury was aware of the erasure of the tape and that the defendant cross-examined Roberts at length concerning the inconsistency. The jury’s awareness of the era*314sure is irrelevant to the question of whether the defendant has been harmed, a question already decided by the trial court in the defendant’s favor, and the jury’s possible speculation as to the contents of the unproduced material is not entitled to any weight. State v. Williamson, supra, 27-28. “Indeed . . . a conclusion that the defendant has not been prejudiced solely because defense counsel utilized other impeachment sources and was given wide latitude in cross-examination would penalize defendants for the best representation their counsel could provide with the available information.” Id., 26. Furthermore, this argument goes to the trial court’s finding that the defendant was harmed by the nondisclosure of the tape, a finding that the state has failed to challenge properly on appeal.
^ Because the trial court, having concluded that the failure to produce the tape was harmful to the defendant, was required either to strike the entire testimony of Roberts or to declare a mistrial, we hold that the trial court abused its discretion in refusing to strike Roberts’ entire testimony.
The judgment of conviction is set aside and the case is remanded for a new trial.
In this opinion Foti, J., concurred.
Practice Book § 755 provides: “If the prosecuting authority elects not to comply with an order of the judicial authority to deliver to the defendant any statement of a witness who has testified or such portion thereof as the judicial authority may direct, the judicial authority shall strike from the record the testimony of the witness, and the trial shall proceed unless the judicial authority, in his discretion, upon motion of the defendant, determines that the interests of justice require that a mistrial be declared.”
General Statutes § 54-86b provides: “(a) In any criminal prosecution, after a witness called by the prosecution has testified on direct examination, the court shall on motion of the defendant order the prosecution to produce any statement oral or written of the witness in the possession of the prosecution which relates to the subject matter as to which the witness has testified, and the court shall order said statement to be delivered directly to the defendant for his examination and use.
“(b) If the prosecution fails to comply with the order of the court, the court shall strike from the record the testimony of the witness and the trial shall proceed unless the court in its discretion shall determine that the interests of justice require that a mistrial be declared.”
Because we agree with the defendant on his first issue, we need not address the defendant’s other appellate issues.
Practice Book § 749 provides: “The term ‘statement’ . . . means: “(1) A written statement made by a person and signed or otherwise adopted or approved by him; or
“(2) A stenographic, mechanical, electrical, or other recording, or a transcription thereof, which is a substantially verbatim recital of an oral statement made by a person and recorded contemporaneously with the making of such oral statement.”
The trial court stated, in this regard: “The reason credibility of this particular witness is so important . . . is because he is the only one that heard the alleged conversation. There is no other testimony. I didn’t hear anything about him being wired or anybody else. So his credibility is of utmost importance. To deprive the defendant of the opportunity to severely test his credibility in an easily identifiable method of cross-examination leads me to the conclusion that I cannot make a finding that this destruction is harmless beyond a reasonable doubt. I can’t say it is harmless because it does not just reflect on identification. It reflects on credibility. [The defendant’s] contention is that . . . he is entitled to explore the possibility that this police officer changed the report after he knew the measured heights of these two individuals to bolster his credibility. It is apparent to me that would be a temptation. I am not saying that the police officer succumbed to it because I don’t have to make a determination in that regard, but clearly it is something that counsel is entitled to explore and cannot now explore because the tape and the notes do not exist. That’s just restating why I believe that I can’t find that the destruction of this tape and notes is harmless, and the court, I believe, it is a difficult decision to apply, but the court seems to acknowledge that when material is destroyed and I can’t see it *311and the Appellate Court can’t see it, it just makes the decision all the more harder; the finding of harmless beyond a reasonable doubt all the more harder or difficult.
“This is not the end of the state’s case. I am only going to strike that portion of the officer’s testimony that relates to identification. The other portions of the testimony are not tainted.” (Emphasis added.) See State v. Williamson, 212 Conn. 6, 562 A.2d 470 (1989), for a discussion of the necessary findings to be made by a trial court, as well as the appropriate burden of proof to be imposed on the proper party, when considering a motion to strike pursuant to Practice Book § 755.
Practice Book § 4013 (a) (1) provides in pertinent part: “If any appellee wishes to (A) present for review alternate grounds upon which the judgment may be affirmed . . . that appellee shall file a preliminary statement of issues within fourteen days from the filing of the appellant’s preliminary statement of the issues.”
The state’s claim also does not warrant plain error review. See Practice Book § 4185. Plain error review is reserved for “truly extraordinary situ*313ations where the existence of the error is so obvious that it affects the fairness and integrity of and public confidence in judicial proceedings.” (Internal quotation marks omitted.) State v. Brown, 19 Conn. App. 640, 644, 563 A.2d 1379, cert. denied, 212 Conn. 821, 565 A.2d 540 (1989). We do not believe this is such a case.