We vacate the judgment of sentence and remand this case for an evidentiary hearing to determine whether the witness Inverso’s identification testimony was the fruit of a violation of appellant’s constitutional rights. If such a violation is found to have occurred, appellant must be granted a new trial. If such violation is found not to have occurred, judgment of sentence shall be reinstated. Appellant and the Commonwealth may appeal from the decision of the eviden-tiary court. Cf. Commonwealth v. Polsky, 485 Pa. 360, 402 A.2d 1003 (1979).