—Judgment, Supreme Court, New York County (James Yates, J.), rendered June 21, 1999, convicting defendant, after a jury trial, of robbery in the second degree, reversed, on the law, and the matter remanded for a new trial.
Defendant’s for-cause challenge of a prospective juror should have been granted. The challenged venire person, after informing the court that his apartment had been burglarized years earlier, stated that he could not pay attention to the case, and could not be a fair juror since he “comets] from a law enforcement family.” On further inquiry, he was asked by the court whether he could listen to witnesses and decide whether the prosecutor had proven defendant’s guilt beyond a reasonable doubt: “No one is going to ask you to say do you like robbery or not like robbery. Everyone knows robbery is wrong and that it’s bad. All we ask the jurors to do is to listen to the witnesses and then decide did the People prove beyond a reasonable doubt that he did that crime, or is there a doubt in you[r] mind, a reasonable one that he didn’t do the crime. Can you do that?”
The juror responded “I don’t know. I can’t say.” At that point, a serious question was raised as to whether this prospective juror had a state of mind which would “preclude him from rendering an impartial verdict based upon the evidence ad*185duced at the trial” (CPL 270.20 [1] [b]). The court was then obligated to either obtain an unequivocal assurance of impartiality or excuse him (People v Arnold, 96 NY2d 358, 363; People v Blyden, 55 NY2d 73, 78-79). Having raised a serious issue regarding his ability or willingness to apply the reasonable doubt standard, the prospective juror was not asked about his ability or willingness to follow the court’s directions. The court asked him whether his strong feelings about law and order would cause him to “vote an innocent man guilty” to which he responded “[n]o.”
When a prospective juror has serious doubt cast on her or his ability to render a fair verdict the trial court is obligated to determine if that individual can provide an unequivocal assertion of impartiality (People v Chambers, 97 NY2d 417; People v Bludson, 97 NY2d 644). Where, as here, a juror repeatedly evidences a predisposition towards the prosecution, cause exists for a challenge. Fairness cannot be measured by asking whether the venire person would do what no decent person would do, viz. convict an innocent person. This question also improperly posits the juror function as determining innocence. The specific problem with this prospective juror was his expressed uncertainty about applying the reasonable doubt burden of proof. When a question is raised regarding a prospective juror’s ability to render an impartial verdict, it is still necessary that the prospective juror in unequivocal terms “must expressly state that his prior state of mind concerning either the case or either of the parties will not influence his verdict, and he must also state that he will render an impartial verdict based solely on the evidence” (People v Biondo, 41 NY2d 483, 485, cert denied 434 US 928). Although the trial judge is experienced and capable, he did not have this biased prospective juror state that he would render an impartial verdict based solely on the evidence.
The dissent is, of course, correct that we afford trial court determinations “due deference” when ascertaining whether a juror is actually biased or attempting to avoid jury service. On this record, however, there is no doubt that the prospective juror’s express bias towards the prosecution stemmed from family relationships and personal experience. The bias expressed was not “abstract” as in People v Williams (63 NY2d 882, 884) and was repeatedly and unequivocally expressed. That the prospective juror also may have been attempting to avoid jury duty did not relieve the court of its obligation to obtain an unequivocal assurance once a serious issue had been raised regarding his ability to render an impartial verdict. The *186question about convicting an innocent man put by the trial court was not reasonably calculated to reveal whether the prospective juror had a bias which would prevent him from reaching an impartial verdict (People v Arnold, 96 NY2d 358, 362; see also, People v Chambers, 97 NY2d 417). In reversing this conviction, we are not reimposing an expurgatory oath (see, People v Blyden, 55 NY2d 73, 77) and we are not imposing new restraints on trial courts. The Court of Appeals has long required that “[p] respective jurors who make statements that cast serious doubt on their ability to render an impartial verdict, and who have given less-than-unequivocal assurances of impartiality, must be excused” (People v Arnold, 96 NY2d 358, 363 [citations omitted]). Despite the fact that the subsequent trial produced legally sufficient evidence of guilt and a verdict abundantly supported by the weight of evidence, we reverse and remand for a new trial. Concur—Tom, J.P., Buckley, Ellerin and Wallach, JJ.