Proceeding pursuant to CPLR article 78 (transferred to this Court by order of the Supreme Court, entered in Albany County) to review a determination of respondent which found petitioner guilty of violating certain prison disciplinary rules.
Petitioner was charged with providing legal assistance without prior approval of the Superintendent or designee in violation of inmate rule 180.17 (7 NYCRR 270.2 [B] [26] [vii]). Contrary to respondent’s assertion, the record before us fails to support the Hearing Officer’s finding that the legal assistance provided by petitioner was unauthorized. Although the testimony at the tier III disciplinary hearing plainly established that petitioner did indeed render legal assistance to certain inmates, neither the misbehavior report filed in connection with the disciplinary proceeding nor the sworn testimony before the Hearing Officer demonstrated that the services provided by petitioner were in violation of the cited rule, and we are unwilling to simply assume that petitioner’s services were in fact unauthorized. Because the challenged determination is not supported by substantial evidence, respondent is directed to expunge all references to this proceeding (see, Matter of Grimmett v Riley, 192 AD2d 831). In light *759of our conclusion on this point, we need not address the remaining arguments advanced by petitioner.
Cardona, White, Mahoney and Casey, JJ., concur. Adjudged that the determination is annulled, without costs, petition granted, and respondent is directed to expunge all references to this proceeding from petitioner’s records and to restore petitioner to his prehearing status.