Appeal by the defendant from a judgment of the Supreme Court, Queens County (Dun-kin, J.), rendered June 20, 1979, convicting him of criminal sale of a controlled substance in the first degree, upon a jury verdict, and imposing sentence.
Ordered that the judgment is affirmed.
Upon the exercise of our factual review power, we find that the evidence established the defendant’s guilt beyond a reasonable doubt and that the verdict was not against the weight of the evidence (see, CPL 470.15 [5]). The defendant was identified by an undercover police officer who purchased drugs
*419from him and by four other officers at the scene. The defendant’s alibi, that he was sick at home at the relevant time, presented a credibility issue for the jury to resolve (see, People v Rosenfeld, 93 AD2d 872, lv denied 59 NY2d 977).
The defendant contends that the court’s instructions to the jury on the alibi defense and on identification testimony deprived him of a fair trial. This issue is not preserved for appellate review since no objection was made to the charge on these grounds (see, People v Nuccie, 57 NY2d 818). Although we agree that the charge should have expressly stated that the burden of disproving the alibi defense and of proving identification was on the People (see, People v Victor, 62 NY2d 374; People v Whalen, 59 NY2d 273), a reversal in the interest of justice is not warranted here in view of the overwhelming proof of guilt (see, People v Crimmins, 36 NY2d 230). Similarly, the contention that the prosecutor’s summation deprived the defendant of a fair trial is not preserved for appellate review. In any event, while the prosecutor should not have alluded to the absence of other potential alibi witnesses (see, People v Titus, 88 AD2d 606), we view the error as harmless under the circumstances of this case.
We find no error in the admission of rebuttal testimony regarding the weather on the night of the drug sale. The testimony was not collateral because it was relevant to the issue of the ability of the police officers to observe the defendant from their surveillance posts on the street (see, People v Schwartzman, 24 NY2d 241, cert denied 396 US 846). The testimony was proper rebuttal because the defendant, through his witnesses, had attempted to prove that it was misty on the night in question (see, People v Harris, 57 NY2d 335, cert denied 460 US 1047).
The defendant contends that the representation of his codefendant by the same attorney at the trial deprived him of a fair trial. We find that the court fulfilled its obligation by inquiring on the record prior to the trial whether the defendants were aware of any potential conflict, and the court was not required to probe any further into possible conflicting defenses (see, People v Gomberg, 38 NY2d 307). Further, the defendant has not demonstrated that a conflict arose during the trial (see, People v Macerola, 47 NY2d 257).
The defendant’s remaining contentions are either unpreserved for review or are without merit. Weinstein, J. P., Spatt and Sullivan, JJ., concur.