Fourth Amendment Center

NACDL's Fourth Amendment Center offers direct assistance to defense lawyers handling cases involving new surveillance tools, technologies and tactics that infringe on the constitutional rights of people in America. The Center is available to help members of the defense bar in bringing new Fourth Amendment challenges.


 To request assistance or additional information, contact


Launched in April 2018, the Fourth Amendment Center seeks to build a robust legal infrastructure to challenge outdated legal doctrines that undermine privacy rights in the digital age. To this end, the Center is available to provide litigation assistance in cases raising new Fourth Amendment concerns, including:



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Defense lawyers with cases involving any of these issues are encouraged to contact the Center. The Center is available to provide consultations and litigation resources as well as direct assistance in support of a defendant’s Fourth Amendment claims. Specifically, the Center may assist in motion practice, preparation for suppression hearings, appellate strategy, brief writing, and oral argument. The Center also provides group trainings for defense lawyers around the country and upon request.


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Learn more about the Center's history, staff, and tech advisory board here.




Watch now: Videos from the Fourth Amendment Center’s May CLE, “Unlocking the Black Box: Challenging Surveillance and Technology in Criminal Cases,” are now available. 

This two-day conference, which the Center hosted alongside the Samuelson Law, Technology, and Public Policy Clinic, features flash talks and panels from leading defense attorneys, scholars and activists. View each event from “Unlocking the Black Box” here.

Read Now: Public Comment from NACDL's Fourth Amendment Center on NIST's "Digital Investigation Techniques: A Scientific Foundation Review"

On July 11, 2022 the Fourth Amendment Center published its response to findings and recommendations contained in a report from the National Institute of Standards and Technology (NIST) on digital forensics. Read the public comment here

Read Now: The United States District Court for the Eastern District of Virginia issued a ruling in United States v. Chatrie (2022)

In United States v. Chatrie, No. 3:19-cr-130 (E.D. Va.), a federal district judge found that law enforcement's use of a geofence warrant to identify a suspect in a bank robbery was unconstitutional and in direct violation of the Fourth Amendment. Mr. Chatrie was represented by federal defenders Laura Koenig and Paul Gill, and Michael Price, Litigation Director for NACDL’s Fourth Amendment Center. More information about the case can be found here

Watch Now: "When Google Searches for You: Challenging Geofence Warrants" Webinar

In 2020, Google received over 11,000 geofence requests from law enforcement agencies across the country, a dramatic increase from just 941 requests in 2018. Geofences search everyone’s location history data to identify devices in an area of interest to law enforcement. The growing use of geofence warrants in investigations raises deep concerns over Fourth Amendment and privacy protections. What strategies can defense lawyers use to challenge this new and invasive investigative technique?

This webinar from November 10, 2021 features Michael Price, the Fourth Amendment Center’s Litigation Director, Laura Koenig, an Assistant Federal Public Defender in Richmond Virginia, and Spencer McInvaille, a Digital Forensic Examiner at Envista Forensics. Jumana Musa, the Director of the NACDL’s Fourth Amendment Center served as moderator for the panel.

Find the rest of our 4AC webinar library here.


Watch Now: "Litigating ShotSpotter Evidence: The Science and the Law" Webinar

ShotSpotter’s forensic gunshot detection systems, deployed in over 100 cities in the U.S., are designed to provide police with real-time alerts of possible gunfire.  But the use of ShotSpotter evidence in criminal trials raises important questions about the reliability of the ShotSpotter forensic method and about the use of ShotSpotter alerts as justification to detain and search people. 


In this webinar from November 10, 2021, Brendan Max, the Chief of the Forensic Science Division of the Cook County Public Defender Office, discusses the reliability of ShotSpotter evidence as well as the legal and 4th amendment strategies that defense lawyers can use to challenge ShotSpotter evidence.


Fourth Amendment Center Publishes Garbage In, Gospel Out: How Data Driven Policing Technologies Entrench Historic Racism and ‘Tech-wash’ Bias in the Criminal Legal System

On September 14, the Fourth Amendment Center published its report exploring the rapid development and deployment of data-driven policing technologies. The report situates its findings within the racist historical context of policing, makes actionable recommendations about the use of data-driven policing technologies, and provides strategies for defense lawyers to use in situations where data-driven policing technology is employed. Garbage In, Gospel Out is based on interviews that the NACDL's Predictive Policing Task Force conducted around the country, and it adopts the Task Force's recommendations on the use of data driven policing technologies. 


Fourth Amendment Center Files Motion to Suppress Evidence Obtained in “Geofence” Warrants Case

In United States v. Chatrie, No. 3:19-cr-130 (E.D. Va.), Okello Chatrie was charged with armed robbery based on Google Sensorvault location data obtained by law enforcement via a geofence warrant. Chatrie is represented by Michael Price, Senior Litigation Counsel for the Fourth Amendment Center, and Laura Koenig, a public defender in the Eastern District of Virginia. According to The Washington Post, prosecutors have called the case the first of its kind.

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Watch Now: "Search, Seize, and Extract: Challenging Law Enforcement Use of Mobile Device Forensic Tools and Technologies in Criminal Cases" Webinar

Last October, a report from the technology and justice non-profit Upturn found that over 2,000 law enforcement agencies in all 50 states had purchased mobile device forensic tools (MDFTs) to search, access, and extract sensitive information from cell phones for use in criminal investigations, often without a warrant and with little to no oversight. The widespread availability and use of MDFTs allow law enforcement access to an immensely broad range of data, such as call activity, texts, photos, videos, passwords, geolocation history, and even content that has been deleted or hidden. How can criminal defense attorneys challenge the use of evidence obtained by MDFTs in criminal cases?

This webinar on May 11, 2021 featured Jennifer Granick, surveillance and cybersecurity counsel with the ACLU Speech, Privacy, and Technology Project, Jerome Greco, a public defender in the Digital Forensics Unit of the Legal Aid Society in New York City, and Harlan Yu, Executive Director of Upturn.

Register for the webinar here.


Watch Now: "Racist by Design: How Systemic Racism and Inherent Biases Manifest in Artificial Intelligence, Machine Learning, and Beyond" Webinar

From policing and sentencing to incarceration and parole, every step of the criminal legal process can now be outsourced to algorithmic decision-making systems. Social media monitoring tools, risk assessment instruments, facial recognition software, and data-driven policing technologies are now being designed and deployed at a rapid pace, with little to no interrogation of the ways in which such technologies can reproduce social hierarchies, amplify discriminatory outcomes, and legitimize violence against marginalized groups that are already disproportionately overpoliced. How can criminal defense attorneys recognize and challenge issues of algorithmic bias, scientific validity, and “dirty data” in criminal cases?

This webinar on April 1, 2021 featured Rashida Richardson, Visiting Scholar at Rutgers Law School and Rutgers Institute for Information Policy and Law, Cathy O’Neil, author, mathematician, and founder of ORCAA, an algorithmic auditing company, and Cierra Robson, a doctoral student in the Sociology and Social Policy program at Harvard University and the Inaugural Associate Director of the Ida B. Wells JUST Data Lab at Princeton University.


Preserving Incarcerated Persons’ Attorney-Client Privilege in the 21st Century: Why the Federal Bureau of Prisons Must Stop Monitoring Confidential Legal Emails​

This new report by NACDL and the Samuelson Clinic makes the case for Congress to act immediately to protect the attorney-client privilege in emails sent between attorneys' offices and people in BOP custody. It also calls for the BOP to stop its practice of requiring incarcerated clients to “voluntarily” agree that their email will be monitored and that attorney-client privilege will not apply to legal emails, just as the government is required to in other contexts.

The full report can be found here.


How to Fix the Internet: "Fixing a Digital Loophole in the Fourth Amendment"

Jumana Musa, Director of the Fourth Amendment Center, recently joined the Electronic Frontier Foundation's podcast How to Fix the Internet to discuss discuss how the third-party doctrine is undermining our Fourth Amendment right to privacy when we use digital services, and how recent court victories are a hopeful sign that we may reclaim these privacy rights in the future.

The recording and transcript of the podcast can be found here.


NACDL Files Amicus Brief in State v. Jackson (2019)

NACDL filed an amicus brief with American Civil Liberties Union of New Jersey and the Association of Criminal Defense Lawyers of New Jersey, arguing that prosecutors wishing to listen in on calls a defendant makes from jail must first get a warrant. This is in support of the State v. Jackson case (Superior Court of New Jersey; Case No. 083286), which argued that defendant Mark Jackson had a reasonable expectation of privacy in the calls he made to his mother from jail. Jackson did not forfeit all privacy rights in his telephone conversations by exposing them to jail staff for security monitoring purposes. Requiring prosecutors to secure warrants in order to access jail calls is the only adequate way to protect the constitutional and policy interests the calls implicate.

 Read the rest of our amicus work here.





Find the rest of our reports and primers here.


CLE Training and Webinar Library


Using Police Technologies to Uncover Law Enforcement Misconduct in Criminal Cases

Since 2017, the Baltimore Public Defender’s Office has called over 2,000 convictions into question related to police misconduct. In one instance, a Baltimore Police Department body-worn camera appeared to show an officer planting drugs at the scene of an arrest. As law enforcement agencies are increasingly using surveillance tools and forensic technologies to identify and arrest suspects in criminal investigations, defense attorneys are faced with the challenge of both defending their clients and holding police accountable for misconduct and abuse. How can criminal defense attorneys turn police technologies on police departments in criminal proceedings? 

This webinar from August 11, 2020 featured Debbie Levi, Director of Special Litigation with the Baltimore City Public Defender, and Ivan Bates, Managing Partner of Bates & Garcia, P.C.

Find the rest of the Center's webinars here.


Combatting the Surveillance State in Criminal Proceedings

This two-day CLE conference discussed the government's use of technologically advanced investigative techniques in criminal cases, and the issues raised by those techniques under the Fourth Amendment and other federal law.  

This CLE was co-sponsored by NACDL and the Berkeley Center for Law and Technology (BCLT), and held at International House, the University of California - Berkeley from November 29 to 30, 2018. 

All of the videos from the conference can be viewed here.


Amicus Briefs


NACDL provides amicus assistance on the federal and state level in those cases that present issues of importance to criminal defendants, criminal defense lawyers, and the criminal justice system as a whole. A selection of NACDL's amicus briefs that address the Fourth Amendment in the digital age are offered below. 


           State v. Jackson                             Jewel v. National Security Agency
        United States v. Henderson                  United States v. Ackerman        
          Dahda v. United States                           Byrd v. United States

 Read the rest of our amicus work here.


Litigation Support


Need help with a case?


The Center is available to provide consultations and litigation resources as well as direct assistance in support of a defendant’s Fourth Amendment claims. Specifically, the Center may assist in motion practice, preparation for suppression hearings, appellate strategy, brief writing, and oral argument. The Center also provides group trainings for defense lawyers around the country and upon request.

To request assistance or additional information, contact





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