Also known as:wiretapping · eavesdropping · wiretap · wiretaps · wiretapped · electronic surveillance · communications interception
Written by attorneys · grounded in primary & secondary sources — see below
Electronic surveillance of private communications that intrudes on a person's reasonable expectation of privacy constitutes a search under the Fourth Amendment and generally requires a warrant.
Sources & Authorities· 8 primary sources
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Cases
Model Codes
Hornbooks
How it applies
Common Examples
6
Directional Microphone in Smoking Area
Wren Wright steps into a glass-walled smoking area on her company campus to make personal calls on her smartphone in a normal tone without speakerphone. Federal agents on a public sidewalk use a high-powered directional microphone to record her conversations for a week without a warrant. Wren moves to suppress the recordings at trial. The court finds the surveillance intruded on her reasonable expectation of privacy and holds it was a search requiring a warrant.
Carrier Reconfiguration for Calls
Walter Washington stands in a city park making sensitive cellphone calls. At federal agents' request, his carrier secretly reconfigures its network to capture and record all calls routed through that cell sector. Agents later use the recordings at Walter's trial. Walter moves to suppress. The court determines the network-level interception of call content invaded his reasonable expectation of privacy and constituted a search.
Hidden Microphone in Law Firm Room
Wendy Wu meets her attorney in a secure conference room at Sky Partners law firm that requires keycard access. Agents install a hidden microphone without a warrant and record their conversations. Wendy moves to suppress the recordings. The court evaluates whether the keycard access and closed door created a reasonable expectation of privacy that the surveillance violated.
Listening Device on Factory Wall
Warren Woods and colleagues use a factory conference room for confidential strategy talks, closing the door and lowering their voices. Agents attach a listening device to the outside wall without a warrant and record the discussions. Warren moves to suppress. The court assesses whether the open collaborative culture and thin walls defeated any reasonable expectation of privacy.
Recorder in Hospital On-Call Room
Wilma Wright uses a secure on-call room in a badge-access hospital wing for private calls after shifts, closing the door and speaking softly. Officers install a hidden recorder without a warrant. Wilma moves to suppress the recordings. The court examines whether her pattern of inviting others and leaving the door ajar undermined a reasonable expectation of privacy.
Audio Recorder in Shared Mailroom
Warren Wu steps into a corner of the shared faculty mailroom and speaks quietly with a student. Campus police hide a recorder in the room without a warrant and capture the conversation. Warren moves to suppress. The court determines whether his low tones created a subjectively reasonable expectation of privacy that society would recognize as objectively reasonable.
Common questions
Frequently Asked
5
When does electronic surveillance of a conversation in a semi-public space constitute a Fourth Amendment search?+
The Fourth Amendment protects people rather than places and is violated when government agents intrude on a person's reasonable expectation of privacy. A person must exhibit a subjective expectation of privacy that society is prepared to recognize as reasonable. Using a directional microphone from a public sidewalk to record calls made in a normal tone without speakerphone invades that expectation and qualifies as a search.
Supporting sources
Does network-level interception of cellphone call content require a warrant?+
Yes. When agents direct a carrier to reconfigure its equipment to capture the content of voice calls that the speaker reasonably attempted to keep private, the interception intrudes on a reasonable expectation of privacy. Society treats the content of ordinary telephone conversations as private when the speaker does not expose the words to public hearing, so the surveillance constitutes a search.
Supporting sources
What factors determine whether a conference room conversation enjoys Fourth Amendment protection from secret recording?+
Courts weigh physical security measures such as keycard access, the practice of closing doors, normal speaking volume, the absence of monitoring warnings, and the room's designated use for confidential consultations. When these steps demonstrate both a subjective expectation of privacy and an objectively reasonable one, warrantless electronic surveillance violates the Fourth Amendment.
Supporting sources
How does an open collaborative workplace culture affect privacy expectations in factory conference rooms?+
The absence of locks, frequent entry by other employees, doors left ajar, and thin walls that allow sound to carry show that conversations were exposed to third parties. These facts defeat both the subjective and objective prongs of the reasonable-expectation test, so attaching a listening device without a warrant does not constitute a search.
Supporting sources
When is a hidden recorder in a hospital on-call room a search?+
A recorder intrudes on a reasonable expectation of privacy when the physician closes the door, speaks in lowered tones, and uses the secure badge-access room for private calls. Inviting others, leaving the door ajar, and failing to install locks or post signs can negate that expectation, rendering the surveillance lawful without a warrant.
Supporting sources
surveillance
was…
were then placed on the telephones of Ring, Greenham, and a third suspect, William Ferguson. Id., at 19-21 (Nov. 18, 1996). In one recorded phone conversation, Ring told Ferguson that…
Criminal Law & ProcedureConstitutional protection of accused persons · Arrest, search and seizureUBEFoundational