Judgment unanimously affirmed. Memorandum: Defendant failed to preserve for our review his contention that the testimony of police investigators bolstered the credibility of prosecution witnesses who testified that they were present when defendant fatally stabbed the victims (see, CPL 470.05 [2]; People v Matusak, 206 AD2d 903, lv denied 84 NY2d 908; People v Marks, 182 AD2d 1122). We decline to exercise our power to review that contention as a matter of discretion in the interest of justice (see, CPL 470.15 [6] [a]; People v Matusak, supra, at 903; People v Valverde, 197 AD2d 920, lv denied 82 NY2d 854).
Supreme Court did not err in admitting into evidence either the blood samples from the victims (see, People v Moyer, 186 AD2d 997, lv denied 81 NY2d 844; see also, People v Julian, 41 NY2d 340, 342-343) or the testimony of a court security deputy regarding a knife that defendant possessed the day before the fatal stabbings. Moreover, even assuming, arguendo, that the court erred in admitting that evidence, any error is harmless because the proof of defendant’s guilt is overwhelming and there is no significant probability that, but for that error, the jury would have acquitted defendant (see, People v Crimmins, 36 NY2d 230, 242). (Appeal from Judgment of Supreme Court, Monroe County, Mark, J.—Murder, 2nd Degree.) Present— Pine, J. P., Lawton, Callahan, Davis and Boehm, JJ.