dissenting.
I agree with the dissenting opinion below that what Lee overheard by means of a radio transmitter surreptitiously introduced and operating, without warrant or consent, within petitioner’s premises, should not have been admitted in evidence. The Fourth Amendment’s protection against unreasonable searches and seizures is not limited to the seizure of tangible things. It extends to intangibles, such as spoken words. In applying the exclusionary rule of Weeks v. United States, 232 U. S. 383, we are primarily concerned with where and how the evidence is seized rather than what the evidence is. Cf. Silverthorne Lumber Co. v. United States, 251 U. S. 385; United States v. Jeffers, 342 U. S. 48; Nueslein v. District of Columbia, 73 App. D. C. 85, 115 F. 2d 690.
It seems clear that if federal officers without warrant or permission enter a house, under conditions amounting to unreasonable search, and there conceal themselves, the conversations they thereby overhear are inadmissible in a federal criminal action. It is argued that, in the instant case, there was no illegal entry because petitioner *766consented to Chin Poy’s presence. This overlooks the fact that Chin Poy, without warrant and without petitioner’s consent, took with him the concealed radio transmitter to which agent Lee’s receiving set was tuned. For these purposes, that amounted to Chin Poy surreptitiously bringing Lee with him.
This Court has held generally that, in a federal criminal trial, a federal officer may testify to what he sees or hears take place within a house or room which he has no warrant or permission to enter, provided he sees or hears it outside of those premises. Olmstead v. United States, 277 U. S. 438. Cf. Hester v. United States, 265 U. S. 57. This holds true even where the officer supplements his hearing with a hearing aid, detectaphone or other device outside the premises. This merely enables him to hear more distinctly, where he is, what reaches him there from wherever it may come. He and his hearing aid pick up the sounds outside of, rather than within, the protected premises. Goldman v. United States, 316 U. S. 129.
In the instant case, Chin Poy, who was lawfully in petitioner’s room, could have testified as to what he, himself, saw or heard there. Yet, if he had been there unlawfully or surreptitiously, without warrant or consent, under conditions amounting to an unreasonable search, he should not be permitted, in this proceeding, to testify even to that. Cf. Gouled v. United States, 255 U. S. 298; Nueslein v. District of Columbia, supra. Similarly, if Lee, under like conditions, without warrant and without authority, entered the room with Chin Poy and, while concealed, overheard petitioner’s conversation with Chin Poy, Lee’s testimony should be excluded. In substance, that is what took place here. Lee’s overhearing of petitioner’s statements was accomplished through Chin Poy’s surreptitious introduction, within petitioner’s laundry, of Lee’s concealed radio transmitter which, without petition*767er’s knowledge or consent, there picked up petitioner’s conversation and transmitted it to Lee outside the premises. The presence of the transmitter, for this purpose, was the presence of Lee’s ear. While this test draws a narrow line between what is admissible and what is not, it is a clearly ascertainable line. It is determined by where the “effects” are seized or, as here, where the words are picked up. In this case the words were picked up without warrant or consent within the constitutionally inviolate “house” of a person entitled to protection there against unreasonable searches and seizures of his person, house, papers and effects. It is inevitable that the line be narrow between, on the one hand, the constitutional right of a person to be free from unreasonable searches and seizures and, on the other, the need for the effective prosecution of crime. Drawing the line is a continuing process. The important thing is that the direction of the line that emerges from successive cases be clear.