Appeal by defendant from a judgment of the County Court, Rockland County (Rubin, J.), rendered June 17, 1980, convicting him of manslaughter in the first degree, upon a plea of guilty, and imposing sentence. Judgment reversed, on the law and as a matter of discretion in the interest of justice, plea of guilty vacated, plea of not guilty reinstated and matter remitted to the County Court, Rockland County, for further proceedings. Prior to the imposition of sentence, the defendant declared that he was not guilty. Moreover, the facts of the case were so consistent with a defense of justification that the trial court observed at the plea proceeding that a serious question of self-defense was presented. Under these circumstances, and in view of the fact that the defendant, who was then 55 years of age, had no prior experience with criminal proceedings, the court should not have accepted the plea and imposed sentence without conducting a further inquiry to determine whether the defendant was aware of the potential justification defense and was deliberately choosing to waive it (see People v Serrano, 15 N.Y.2d 304; People v Quiles, 72 A.D.2d 610; People v McDougle, 67 A.D.2d 989). Mollen, P.J., Titone, Thompson and Gulotta, JJ., concur.