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Respondent(Knotts) and two codefendants(Darryl Petschen, Tristan Armstrong)
were charged with conspiracy to manufacture controlled substances.
The 3M company, which is a manufacturer of chemicals, alerted a narcotics
officer working for the Minnesota Bureau of Criminal Apprehension that
Armstrong, who was a former 3M employee, had been stealing controlled
substances which could be used to manufacture illegal drugs.
Visual surveillance later revealed that Armstrong would purchase similar
chemicals from the Hawkins Chemical company in Minneapolis.
Narcotics officers then observed that after the purchase had been made,
Armstrong would transport the chemicals to Petschen.
With the consent of the Hawkins company, narcotics officers placed a beeper
inside of a five gallon container of chloroform, which was one of the drugs called
into question.
The Hawkins company would then place the chloroform that Armstrong
purchased in this specific container.
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Officers followed Armstrong after the purchase had been made,
maintaining visual surveillance and using a monitor receiving the beeper
signals.
Armstrong proceeded to Petschen’s house, where the chemicals were
transferred to his car, which police then followed east across the St. Croix
river into Wisconsin.
At this time police ended their visual surveillance and the beeper signal
was lost, but later picked up an hour later.
The signal was now stationary at a cabin owned by the respondent.
Police then obtained a search warrant and found chemicals and laboratory
equipment used to make controlled substances.
The respondent was convicted of conspiring to manufacture controlled
substances.
The Court of Appeals ruled the search was unconstitutional.
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Respondent argued that the beeper enabled police to
be more effective in detecting crime.
He attacks the use of the beeper to determine the
chloroform had come to rest on his property.
He states the government overlooked the fact of
using the beeper to determine the chemicals were
located on the respondents property, which has the
greatest protection under the fourth amendment.
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The movement of Armstrong and Petschen in their cars has no
expectation of privacy because all of the movements were on public
roads.
Visual surveillance could have viewed the defendants travelling to all of
their destinations.
If police had followed Petschen the whole time, they could have viewed
him travel to Knotts cabin.
The beeper is simply a more effective way of observing what is already
public.
Nothing the obtained from the beeper signal revealed anything about the
inside of the cabin or anything that could not have been revealed through
visual surveillance.
 The
Supreme court of the
United States of America
ruled that no expectation of
privacy was violated and the
ruling of the court of appeals
was reversed.