(concurring). I concur in the result reached by the court. I think it useful to add a few comments concerning the admissibility of the fruit of “private” searches under art. 14 in general and the scope of the common carrier exemption under G. L. c. 272, § 99 D 1 a, in particular.
Article 14 of the Massachusetts Declaration of Rights provides: “Every subject has a right to be secure from all unreasonable searches, and seizures, of his person, his houses, his papers, and all his possessions. All warrants, therefore, are contrary to this right, if the cause or foundation of them be not previously supported by oath or affirmation; and if the order in the warrant to a civil officer, to make search in suspected places, or to arrest one or more suspected persons, or to seize their property, be not accompanied with a special designation of the persons or objects of search, arrest, or seizure: and no warrant ought to be issued but in cases, and with the formalities prescribed by the laws.”
This court has recognized previously that our State Constitution may, in some circumstances, afford greater protections to individuals than are required by the Fourth Amend*227ment to the United States Constitution. See Commonwealth v. Soares, 377 Mass. 461 (1979); Commonwealth v. Ortiz, 376 Mass. 349, 358 (1978). In particular, we have made reference, on another occasion, to our ability to “adopt a broader definition of search under art. 14 of the Declaration of Rights than prevails under the Constitution of the United States.” District Attorney for the Plymouth Dist. v. New England Tel. & Tel. Co., 379 Mass. 586, 589 (1980). Id. at 595 n.l (Hennessey, C.J., concurring), and at 597 n.l (Liacos, J., dissenting). Compare Smith v. Maryland, 442 U.S. 735, 745-746 (1979).
The majority conclude that “[bjecause the actions of the telephone company cannot be viewed as State action, the evidence derived from placement of the cross frame unit trap should not be suppressed on the basis of a violation of either the Fourth Amendment or of art. 14.” Supra at 222. Implicit in this conclusion is the recognition that a search occurred, albeit not one in which the Commonwealth was involved sufficiently to trigger art. 14. Contrast Smith v. Maryland, supra at 739 n.4, 745-746 (where pen register installed by telephone company at police request, State action present, although no search held to have taken place); Dear-horn Heights v. Hayes, 82 Mich. App. 253 (1978) (police requested telephone company action). Here, the telephone company placed the cross frame unit trap on the line of a customer at her request. When an employee of the company determined that the annoying phone calls were coming from the defendant’s telephone, the customer signed complaints against the defendant, alleging three separate criminal violations of G. L. c. 269, § 14A. A keeper of the records from the company testified in court in response to a subpoena duces tecum issued by the district attorney for the Plymouth District. If the company is to be deemed to be acting on behalf of another in this case, that other party is not the Commonwealth. Accord, Von Lusch v. C & P Tel. Co., 457 F. Supp. 814, 818 (D. Md. 1978); State v. Droutman, 143 N.J. Super. 322 (1976). The court correctly concludes that this record fails to establish that State action was *228involved in the installation and use of the cross frame unit trap. Cf. Commonwealth v. Richmond, 379 Mass. 557, 561-562 (1980); Commonwealth v. Weiss, 370 Mass. 416, 419 (1976).
Although no violation of art. 14 is shown in this case, it should be clear that art. 14 may not, in all circumstances, permit the introduction of evidence seized unlawfully by a private party. See Burdeau v. McDowell, 256 U.S. 465, 476-477 (1921) (Brandeis & Holmes, JJ., dissenting). The justification most commonly given for the nonapplication of the exclusionary rule to the fruits of private searches is that no deterrent purpose would be served by its application to the actions of private persons. See 1 W.R. LaFave, Search and Seizure § 1.6, at 110-114 (1978). This may be true, generally, at least where the government did not participate in or instigate the search. Id. However, Burdeau may lose its validity where the “private” search, although carried out by a private entity, is pursuant to a public policy, the dominant purpose of which is the prevention of crime. See W.R. LaFave, supra at 129. In this vein, at least one State court has suppressed the fruits of an unlawful “private” search, which was “an exercise of sovereignty allowed by the State to private citizens,” as violative of the provisions of its State Constitution. People v. Zelinski, 24 Cal. 3d 357, 367-368 (1979). Cf. Sullivan v. District Court of Hampshire, 384 Mass. 736, 741 (1981).
The court holds today, in accordance with our previous decisions, that the use of pen registers and cross frame unit trap devices is regulated by G. L. c. 272, § 99. Supra at 223. See District Attorney for the Plymouth Dist. v. New England Tel. & Tel. Co., supra at 591-592. Protection of the fundamental privacy interests secured by art. 14 is enhanced by the limitations imposed on the use of such devices by G. L. c. 272, § 99. See id. at 598-600 (Liacos, J., dissenting) .
We have noted that G. L. c. 272, § 99 D 1 a, “expresses the intention that an employee of any communication common carrier may properly without a warrant intercept, dis*229close or use the contents of a communication where that interception, disclosure or use is necessary to prevent the use of that company’s facilities in violation of G. L. c. 269, § 14A.” Commonwealth v. Coviello, 362 Mass. 722, 724 n.l (1973). The same subsection also provides that it shall not be a violation of § 99 for a telephone company employee to intercept or disclose a communication where such action is “a necessary incident to the rendition of service or to the protection of the rights or property of the carrier of such communication.” Thus, under this exemption, the telephone company is authorized to intercept and disclose communications in furtherance of its dual interest in protecting the integrity of its lines and to prevent the use of its property for criminal purposes.
It should be kept in mind, however, that a significant but oft-ignored inquiry in the determination whether certain conduct constitutes State action is “whether federal or state law can validly distribute authority between governmental and private actions as it purports to do.” L.H. Tribe, American Constitutional Law § 18.3, at 1158 (1978). The State has authorized the company to intercept communications for two limited purposes. Where, as here, the record discloses that the dominant purpose behind the search by the company is the protection of its lines and the rendition of quality service, and the resulting criminal prosecution was merely incident to that company purpose, the use of the evidence obtained did not offend art. 14 of the Declaration of Rights and is properly within the exception to the warrant requirements of G. L. c. 272, § 99. Compare G. L. c. 272, § 99 E - N, with G. L. c. 272, § 99 D 1 a. Accord, United States v. Harvey, 540 F.2d 1345, 1352 (8th Cir. 1976). Under other circumstances, with a record which disclosed an intent not to vindicate the company’s interests, but rather to further a State interest in the prosecution of wrongdoers, I would reach a different conclusion. See People v. Zelinski, supra.