concurring.
I join the opinion of the Court, reserving judgment, however, on some of the Court’s general remarks about the scope and purpose of the exclusionary rule which the Court has fashioned in the process of enforcing the Fourth Amendment.
Also, although the Court puts the matter aside in the context of this case, I think an additional word is in order concerning the matter of interrogation during an investigative stop. There is nothing in the Constitution which prevents a policeman from addressing questions to anyone on the streets. Absent special circumstances, the person approached may not be detained or frisked but may refuse to cooperate and go on his way. However, given the proper circumstances, such as those in this case, it seems to me the person may be briefly detained against his will while pertinent questions are directed to him. Of course, the person stopped is not obliged to answer, answers may not be compelled, and refusal to answer furnishes no basis for an arrest, although it may alert the officer to the need for continued observation. In my view, it is temporary detention, warranted by the circumstances, which chiefly justifies the protective frisk for weapons. Perhaps the frisk itself, where proper, will have beneficial results whether questions are asked or not. If weapons are found, an arrest will fol*35low. If none are found, the frisk may nevertheless serve preventive ends because of its unmistakable message that suspicion has been aroused. But if the investigative stop is sustainable at all, constitutional rights are not necessarily violated if pertinent questions are asked and the person is restrained briefly in the process.