Appeal by defendant from a judgment of the County Court, Westchester County, rendered February 17, 1977, convicting him of criminal sale of a controlled substance in the fifth degree, upon his plea of guilty, and imposing sentence. The appeal also brings up for review an order of the same court, dated September 21, 1976, which denied, without a hearing, defendant's motion to dismiss the indictment on the ground of prejudicial delay. Case remanded to the County Court for a hearing and a new determination on defendant's motion to dismiss the indictment upon the ground there had been prejudicial delay, and appeal held in abeyance in the interim. The mere claim by the District Attorney that the delay was caused by unsuccessful efforts to locate the defendant furnished an insufficient basis to deny, without a hearing, the motion to dismiss the indictment upon the ground of prejudicial delay, as a potential for prejudice to the defendant's rights appears and has been raised. This is especially true in narcotics cases with their concomitant on-going investigations (cf. People v Charette, 57 A.D.2d 594; People v Townsend, 38 A.D.2d 569). Martuscello, J.P., Rabin, Cohalan and Hawkins, JJ., concur.