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United States v. Karo

Citation. United States v. Karo, 468 U.S. 705, 104 S. Ct. 3296, 82 L. Ed. 2d 530, 52 U.S.L.W. 5102 (U.S. July 3, 1984)
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Brief Fact Summary.

The DEA placed a beeper in a can of ether which informant told them was to be used to extract cocaine from clothing imported into the United States. The beeper lead them to a house which the DEA then obtained a warrant to search.

Synopsis of Rule of Law.

Installing a beeper in a container of chemicals with an original owner’s consent is not a search for Fourth Amendment purposes. However, if information is obtained through use of a beeper device which could not have been obtained through visual surveillance, that is a search for Fourth Amendment purposes.


A government informant told the DEA that Respondents Karo, Horton and Harley had ordered 50 gallons of ether to be used to extract cocaine from clothing imported into the U.S. With the informant’s consent, they placed a can containing a beeper in one of the cans of the shipment. The DEA saw Respondent Karo pick up the ether shipment and observed the shipment moving to various places until it reached the home of another respondent, Steele. Agents used the beeper information in obtaining a warrant to search the house where cocaine was seized, resulting in indictments for various offenses for the Respondents. The New Mexico District Court granted the pretrial motion to suppress the evidence on grounds that the warrant was invalid and that the seizure was the tainted fruit of the unauthorized installation of the beeper. The Tenth Circuit Court of Appeals affirmed except as to the monitoring of the beeper in the private dwellings and storage lockers. The Government was then g
ranted certiorari.


Does installation of a beeper in a container of chemicals with the consent of the original owner constitute a search for Fourth Amendment purposes when the container is delivered to a buyer with no knowledge of its presence?
Does monitoring of a beeper fall within the reach of the Fourth Amendment when visual surveillance could not have produced the information produced?


Reverse the decision of the Court of Appeals.
No, transfer of a can containing an unmonitored beeper conveyed no information the recipient wished to keep private, so it conveyed no information at all. It also did not interfere with a possessory interest in a meaningful way so no Fourth Amendment interest was infringed.

Yes, it would be a search to surreptitiously enter a residence without a warrant to verify that a container was there, but that is not what was done here because the chain of custody could have been observed by merely watching the ether travel on the public highways to the house from the outside of the curtilage.


Justice John Paul Stevens stated that the beeper’s installation was a search and a seizure for Fourth Amendment purposes. There was an interference with possessory rights, specifically the possessory right to exclude.
Concurrence. Justice Sandra Day O’Connor argued that the mere installation of the beeper did not implicate the Fourth Amendment, but only when the beeper is activated to track the movements of the container will such interests be infringed on. Because here the container was moved on the public highways where there is no reasonable expectation of privacy there is no valid Fourth Amendment unreasonable search or seizure argument.


This case, when coupled with the result in United States v. Knotts, 460 U.S. 276 (1983), show a strong leaning by the Supreme Court for the use of beepers in many cases not constituting a search for Fourth Amendment purposes.

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