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Police Technology Case Law Center

A practical legal research resource addressing the Fourth Amendment, digital evidence, location tracking, surveillance technology, artificial intelligence, and other emerging technologies used in public safety.

Fourth Amendment Digital Evidence Location Data ALPR Pole Cameras Cell Phones Emerging Technology

Technology Changes. Fourth Amendment Principles Endure.

Police technology continues to evolve faster than the case law governing it. Courts are increasingly required to apply traditional Fourth Amendment principles to technologies capable of collecting, aggregating, analyzing, and retaining information at a scale that was previously impossible.

The Shield Police Technology Case Law Center is designed for law enforcement leaders, investigators, attorneys, analysts, policy makers, and risk managers who need more than a citation. Each full case summary explains the facts, procedural history, legal issue, holding, reasoning, operational significance, and practical implications for public safety agencies.

How to Use This Resource

Search by case name, technology, legal doctrine, or issue. You can also filter the library by technology category and court.

Individual summaries are written to identify both the governing rule and the operational decisions agencies should evaluate when adopting or using the technology involved.

Major Supreme Court Development

Chatrie v. United States — Geofence Location Data

On June 29, 2026, the United States Supreme Court held that law enforcement conducted a Fourth Amendment search when officers obtained location data associated with Okello Chatrie from Google. The decision represents an important development in the Court's location-privacy jurisprudence and has implications extending beyond geofence warrants.

Read the Chatrie case summary →

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Case Library

Select a case to open the complete Shield case analysis.

U.S. Supreme Court Geofence Location Data

Chatrie v. United States

U.S. Supreme Court · June 29, 2026

Supreme Court consideration of law enforcement acquisition of Google location information through a geofence warrant.

Key issue: Whether obtaining location information identifying devices present within a defined geographic area constitutes a Fourth Amendment search.
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U.S. Supreme Court CSLI Location

Carpenter v. United States

585 U.S. 296 (2018)

The Court confronted the application of the third-party doctrine to historical cell-site location information capable of chronicling a person's movements.

Key doctrine: Digital location information can receive Fourth Amendment protection despite being held by a third-party service provider.
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U.S. Supreme Court GPS Surveillance

United States v. Jones

565 U.S. 400 (2012)

The government installed and used a GPS tracking device on a vehicle, producing a foundational modern Fourth Amendment decision involving technology-enabled location surveillance.

Key doctrine: Physical trespass undertaken to obtain information can constitute a Fourth Amendment search.
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U.S. Supreme Court Cell Phones Digital Search

Riley v. California

573 U.S. 373 (2014)

The Court examined whether the search-incident-to-arrest doctrine permits warrantless examination of the digital contents of a seized cell phone.

Key doctrine: Digital devices differ qualitatively and quantitatively from traditional physical objects carried by an arrestee.
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First Circuit Cell Phones

United States v. Wurie

Cell-phone search litigation preceding Riley

One of the principal appellate decisions that preceded the Supreme Court's modern treatment of cell-phone searches in Riley.

Operational relevance: Illustrates the doctrinal shift from treating phones as ordinary physical containers to recognizing the privacy significance of digital data.
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Seventh Circuit Cell Phones

United States v. Flores-Lopez

Federal appellate decision

An early federal appellate decision examining the extent to which law enforcement could obtain information from a cellular telephone following an arrest.

Why it matters: Provides historical context for the legal rules that ultimately developed in Riley.
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First Circuit Pole Camera Long-Term Surveillance

United States v. Moore-Bush

First Circuit

A significant federal appellate treatment of prolonged pole-camera surveillance directed toward a residence.

Key issue: Whether aggregation of public-view video over an extended period can transform conventional visual observation into a Fourth Amendment search.
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Seventh Circuit Pole Camera

United States v. Tuggle

Seventh Circuit

Addresses sustained video surveillance of a residence through government-operated cameras positioned in public locations.

Key issue: The constitutional significance of duration, aggregation, and technological enhancement of observations visible from public vantage points.
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Sixth Circuit Pole Camera

United States v. Houston

Sixth Circuit

Examines warrantless video surveillance of property from a lawful public vantage point.

Operational relevance: Frequently cited in evaluating whether conventional pole-camera surveillance implicates a reasonable expectation of privacy.
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Federal Court Video Surveillance

United States v. Diggs

Federal surveillance decision

Addresses Fourth Amendment limits implicated by technology-assisted visual surveillance.

Key issue: When surveillance of conduct exposed to public observation becomes constitutionally significant because of technology, scope, or duration.
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State Court Pole Camera California

People v. Maxon

California surveillance litigation

California litigation addressing prolonged pole-camera surveillance and the privacy implications of sustained technological observation of a residence.

Agency significance: Demonstrates why state constitutional law and state privacy doctrines must be evaluated independently from the federal Fourth Amendment baseline.
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State Court Surveillance

State v. Hay

State constitutional surveillance decision

Addresses the constitutional consequences of technologically enhanced surveillance conducted over time.

Key lesson: Agencies should consider federal law, state constitutional protections, and statutory privacy requirements before deploying sustained surveillance technology.
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U.S. Supreme Court Database Access CFAA

Van Buren v. United States

593 U.S. 374 (2021)

The Court addressed the meaning of exceeding authorized access under the federal Computer Fraud and Abuse Act in a case involving a law enforcement officer's use of a database.

Operational significance: Important distinction between unauthorized access to information and misuse of information that a user is otherwise technically authorized to obtain.
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U.S. Supreme Court Cloud Data Digital Evidence

United States v. Microsoft Corp.

Cloud-data jurisdiction litigation

Litigation involving government access to electronic communications stored by a U.S. technology provider outside the United States.

Operational relevance: Illustrates the jurisdictional and statutory complexities that arise when digital evidence is stored across national borders.
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Ninth Circuit Web Data CFAA

hiQ Labs, Inc. v. LinkedIn Corp.

Ninth Circuit

Litigation concerning automated collection of information available on publicly accessible web pages and the scope of federal computer-access restrictions.

Why it matters: Relevant to automated data collection, open-source intelligence tools, web scraping, and access-control analysis.
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Federal Court Automated Research CFAA

Sandvig v. Barr

Federal computer-access litigation

Litigation involving researchers seeking to use automated techniques and fictitious accounts to evaluate algorithmic discrimination on websites.

Why it matters: Helps define the relationship between website restrictions, automated data collection, investigative research, and federal computer-access law.
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Technology Areas Covered

Location Tracking

CSLI, GPS, geofence warrants, location histories, device location data, and aggregation of movement information.

Video Surveillance

Pole cameras, prolonged surveillance, public-view observations, aggregation, and mosaic-theory concerns.

ALPR & Vehicle Intelligence

Automated license plate readers, historical plate databases, vehicle tracking, retention, sharing, and large-scale aggregation.

Cell Phones

Device searches, digital contents, location data, search incident to arrest, warrants, and extraction technologies.

Digital Evidence

Cloud records, electronic communications, service-provider information, cross-border evidence, and third-party data.

Computer & Data Access

Government databases, automated data collection, open web information, authorized access, and computer-use restrictions.

Legal Research Notice: The Shield Police Technology Case Law Center is provided for educational and training purposes. It is not legal advice and does not substitute for review by agency counsel. Case law, statutes, regulations, and technology change rapidly. Agencies should verify current authority in the applicable jurisdiction before relying upon any legal proposition or implementing a technology-related practice.
Last reviewed: August 9, 2026