Facts of the Case

Provided by Oyez

Tristan Armstrong, a former employee of the 3M Company, which manufactures chemicals in St. Paul, came under suspicion for stealing chemicals that could be used to manufacture illegal drugs. The company notified a narcotics agent, and further investigation determined that Armstrong had been purchasing similar chemicals from the Hawkins Chemical Company in St. Louis. With the consent of Hawkins Chemical Company, narcotics agents installed a radio transmitter in the container of chloroform that Armstrong would receive. By tracking the radio transmitter, officers were able to track Armstrong delivering the chloroform to Darryl Petschen. Petschen drove it to a cabin owned by Leroy Carlton Knotts in Shell Lake, Wisconsin. Relying on this information, the officers obtained a search warrant for the cabin and found a fully operable drug-manufacturing lab.

Knotts was convicted in district court after the court denied his motion to suppress the evidence. The United States Court of Appeals for the Eighth Circuit reversed the conviction and held that the monitoring of the radio transmitter violated Knotts’ Fourth Amendment rights.

Questions

  1. Does police planting and tracking of a radio transmitter violate the Fourth Amendment?

Conclusions

  1. No. Justice William H. Rehnquist delivered the unanimous opinion. The Court held that the use of the radio transmitter to track the movements of a suspect in a car falls under the privacy expectations for a vehicle, which are less than those of a house. Since the radio transmitter in this case was used primarily to ascertain where the chloroform traveled and where it stopped, the surveillance did not violate Knotts’ right to privacy in his home. Additionally, the use of the radio transmitter did not serve any function that the police could not have performed visually; the transmitter merely made the process easier.

    Justice William J. Brennan, Jr. concurred in the judgment and wrote that, while he agreed with the majority’s decision concerning the use of the radio transmitter, he found its original installation to be on shakier constitutional ground. He argued that the installation of the radio transmitter represented a significantly larger intrusion upon a person’s privacy. Justice Thurgood Marshall joined in the opinion concurring in judgment.

    Justice Harry A. Blackmun also concurred in judgment and argued that the majority’s opinion unnecessarily referred to the “open fields” doctrine that was a major issues in two cases the Court had yet to hear. He wrote that he did not wish either side in those two cases to gain legitimacy from this one. Justice William J. Brennan, Jr., Justice Thurgood Marshall, and Justice John Paul Stevens joined in the concurrence in judgment.

    Justice John Paul Stevens concurred in the judgment and wrote that the majority opinion’s implication that the this case involved the “open field” doctrine was false. He also argued that the use of technology to augment officers’ abilities was not always automatically constitutionally sound. Justice William J. Brennan, Jr. and Justice Thurgood Marshall joined the opinion concurring in judgment.