Appeal by defendant from a judgment of the Supreme Court, Suffolk County (D'Amaro, J.), rendered June 15, 1977, convicting him of endangering the welfare of a child, upon a jury verdict, and imposing sentence. Judgment reversed, as a matter of discretion in the interest of justice, and new trial ordered. Defendant was deprived of a fair trial as a result of the testimony adduced at trial from a child psychiatrist and the trial prosecutor's summation. During the course of her testimony on the People's direct case, the child psychiatrist made direct reference to the complainant's ability to tell the truth. Under the circumstances of this case, such testimony served to bolster the complainant's credibility and interfered with the jurors' duty to assess the complainant's veracity, unfettered and without undue influence by the opinion of an expert. Furthermore, the prosecutor exceeded the bounds of proper summation by playing heavily upon the emotions of the jurors in an obvious attempt to align them with the complainant and to thus bolster his testimony. In an emotionally charged prosecution such as this, a prosecutor must scrupulously avoid the introduction of extraneous and prejudicial matter into his summation. Lazer, J.P., Gulotta, Cohalan and Bracken, JJ., concur.