Determination unanimously confirmed and petition dismissed. Memorandum: The determination of respondent is supported by substantial evidence (see generally, Matter of Perez v. Wilmot, 67 N.Y.2d 615; People ex rel. Vega v. Smith, 66 N.Y.2d 130, 139). Petitioner's denial of the charges presented an issue of credibility for the Hearing Officer to resolve. The Hearing Officer was entitled to credit the charging officer's report and the testimony of another correction officer (see, Matter of Perez v. Wilmot, supra). Petitioner further challenges the propriety of the penalty imposed. He failed to raise that issue, however, either on his administrative appeal or in his petition. Petitioner thereby failed to exhaust his administrative remedies and this Court has no discretionary power to reach that issue (see, Matter of Nelson v. Coughlin, 188 A.D.2d 1071, appeal dismissed 81 N.Y.2d 834).