Silverman v. United States - 365 U.S. 505, 81 S. Ct. 679 (1961)

Rule:

At the very core of the Fourth Amendment stands the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion. The Supreme Court has never held that a federal officer may without warrant and without consent physically entrench into a man's office or home, there secretly observe or listen, and relate at the man's subsequent criminal trial what was seen or heard. 

Facts:

The police had reason to suspect that defendants' premises were being used as the headquarters for a gambling operation. The police gained permission from the owner of the vacant adjoining row house to use it as an observation post. The officer then installed a "spike mike" to listen to what was going on at the house next door. The "spike mike" was attached with an amplifier, a power pack, and earphones. It was inserted into a crevice until it made contact with a heating duct that served the house occupied by defendants. At the trial, the police were permitted to describe incriminating conversations engaged in by defendants. The defendants' motion to suppress the evidence was denied. (166 F Supp 838.) The defendants were found guilty in the District Court and their convictions were affirmed by the Court of Appeals.

Issue:

Was the eavesdropping by the police with a "spike mike"  in violation of the Fourth Amendment rights of the defendants?

Answer:

Yes

Conclusion:

The court reversed the convictions, holding that defendants' Fourth Amendment rights were violated because the eavesdropping was accomplished by means of an unauthorized physical penetration into the premises occupied by defendants. Although the "spike mike" touching the heating duct was a minor intrusion, the court found that it still constituted an actual intrusion into a constitutionally protected area.