ACLU of Massachusetts Launches Comprehensive Legal Toolkit to Combat Undisclosed Law Enforcement Surveillance Technologies

The American Civil Liberties Union (ACLU) of Massachusetts has announced the release of a specialized online toolkit for criminal defense attorneys, a first-of-its-kind initiative designed to identify and challenge the use of secretive surveillance technologies in police investigations. This digital resource, comprised of meticulously drafted legal motions, aims to bridge the gap between rapid technological adoption by law enforcement and the slower pace of judicial oversight. The toolkit covers a broad spectrum of tools, including facial recognition software, automatic license plate readers (ALPRs), cell-site simulators, gunshot detection systems, and artificial intelligence-driven report writing. By providing a standardized framework for discovery and preservation, the ACLU seeks to ensure that defendants’ constitutional rights are not bypassed by the use of "black box" technologies that often remain hidden from the judicial record.

The Push for Transparency in Digital Forensics

The core of the ACLU’s initiative is a library of password-protected legal motions available exclusively to verified defense counsel. These documents are designed to be filed in court to compel prosecutors to disclose whether specific surveillance technologies were utilized to identify, track, or build a case against a defendant. According to Jennifer Herrmann, a staff attorney at the ACLU of Massachusetts and a co-author of the toolkit, the project operates on a dual-track strategy. While the organization continues to lobby municipal governments to ban or restrict tools like the Flock Safety ALPR network or the ShotSpotter gunshot detection system, the toolkit arms the defense bar with the means to expose these tools when they have already been deployed in the field.

The legal strategy rests on the "Brady Rule," established by the United States Supreme Court in the 1963 landmark case Brady v. Maryland. This constitutional requirement mandates that prosecutors turn over all evidence favorable to the accused, including information that could impeach the credibility of government witnesses or the reliability of the methods used to collect evidence. Despite this bedrock principle, the ACLU argues that modern surveillance often circumvents these requirements through "parallel construction"—a process where police use secret tools to find evidence and then build a separate, public-facing narrative to explain how they obtained it without mentioning the original technology.

A Chronology of Surveillance and Judicial Lag

The necessity of the toolkit is underscored by what legal scholars describe as a chronic lag between the deployment of new police tools and the establishment of legal precedents governing their use.

• Late 1990s: Mobile phone usage becomes widespread across the United States.
• 2007–2015: The Baltimore Police Department uses cell-site simulators (Stingrays) more than 4,300 times, frequently hiding the technology’s use from judges and defense attorneys under FBI-mandated nondisclosure agreements.
• 2014: The Massachusetts Supreme Judicial Court (SJC) breaks from federal trends by requiring police to obtain a warrant for cell phone location data in Commonwealth v. Augustine.
• 2018: The U.S. Supreme Court finally establishes a federal warrant requirement for historical cell-site location information in Carpenter v. United States, decades after the technology became common.
• 2020: The Massachusetts SJC hears Commonwealth v. McCarthy, a pivotal case regarding the "mosaic theory" of surveillance as applied to automatic license plate readers.
• 2024: The Massachusetts SJC bars prosecutors from refiling charges against a defendant after police refused to disclose details regarding fake social media profiles used for surveillance.
• 2025: The U.S. Supreme Court rules 6-3 that "geofence warrants"—which compel companies like Google to provide data on every device in a specific area—constitute a search under the Fourth Amendment.

This timeline illustrates a persistent pattern: law enforcement often operates in a legal vacuum for years or even decades before the judiciary clarifies the constitutional boundaries of new investigative methods. The ACLU’s toolkit is intended to accelerate this process by forcing these issues into the courtroom earlier in the litigation cycle.

Specific Technologies and the Secrecy Infrastructure

The toolkit addresses several categories of technology that have historically been shielded from public view. One of the most prominent is the "Stingray" or cell-site simulator. These suitcase-sized devices mimic cell towers to trick nearby phones into connecting to them, allowing police to locate individuals with high precision. For years, the FBI required local law enforcement agencies to sign secrecy agreements that instructed prosecutors to drop criminal cases rather than reveal the existence of the technology in open court. Records obtained by the ACLU indicate that these agreements remained in effect as recently as 2020.

Another area of concern is commercial location data. Tools like Fog Reveal allow investigators to map an individual’s movements by accessing a massive database of app-harvested location data sold by commercial brokers. In one 2017 murder investigation in Missouri, the use of this tool was entirely absent from trial exhibits, despite its role in the investigation. Similarly, facial recognition technology has been criticized for its "black box" nature. In the 2022 case of Randal Quran Reid in Louisiana, an arrest warrant attributed his identification to a "credible source" rather than the facial recognition software that had actually misidentified him, leading to his wrongful incarceration for nearly a week.

The toolkit also targets AI-generated evidence. Axon, a major law enforcement technology provider, recently introduced "Draft One," a tool that uses artificial intelligence to draft police reports based on body camera audio. Critics, including the Electronic Frontier Foundation, have noted that the software is designed to delete the original AI-written draft once a human officer edits it. This design choice, according to Axon representatives, was intended to avoid "disclosure headaches," but privacy advocates argue it destroys potentially exculpatory evidence regarding how a report was formulated.

Data Retention and the "Vanishing Evidence" Problem

A significant portion of the ACLU’s toolkit is dedicated to "preservation motions." These are legal demands that require government agencies and private vendors to save surveillance data before it is automatically purged. This is particularly relevant for systems like Flock Safety, which defaults to a 30-day retention period for license plate data, and ShotSpotter, which has previously claimed that its gunshot detection data is the proprietary property of the vendor rather than the municipality.

Gideon Epstein, Technology for Liberty policy counsel at the ACLU of Massachusetts and a co-author of the toolkit, emphasizes the paradoxical nature of data retention. While the ACLU generally advocates for shorter retention periods to protect public privacy—lobbying for ALPR data to be deleted within 48 hours—they recognize that once a person is charged with a crime, that same data may be the only evidence capable of exonerating them. If the data is deleted before a defense attorney is appointed, the opportunity for a fair trial may be permanently lost.

Analysis of Legal Implications and Precedents

Massachusetts has emerged as a critical battleground for digital privacy, often setting precedents that influence national law. The state’s highest court has consistently ruled that the "mosaic theory"—the idea that the collection of many small pieces of data can reveal a comprehensive and private picture of a person’s life—requires constitutional protection.

In 2024, the Massachusetts Supreme Judicial Court took the unprecedented step of permanently dismissing drug and firearm charges because the police failed to comply with discovery orders regarding their use of racially biased social media avatars. Furthermore, the court ruled that defendants have the right to a "Daubert-style" hearing to force prosecutors to prove the scientific reliability of ShotSpotter technology before its data can be admitted as evidence.

The ACLU’s toolkit is built upon these Massachusetts-specific rulings, but the organization notes that the underlying legal theories can be adapted for use in other jurisdictions. By standardizing the language of these motions, the ACLU hopes to create a national ripple effect, forcing more transparency from law enforcement agencies nationwide.

Broader Impact on the Justice System

The release of this toolkit comes at a time of heightened scrutiny regarding the intersection of technology and civil rights. The recent U.S. Supreme Court ruling on geofence warrants has left lower courts to determine the specific requirements for such warrants, and the ACLU’s new geofencing motions are expected to play a major role in shaping those upcoming decisions.

The broader implication of the toolkit is a shift in the power dynamic of discovery. Historically, defense attorneys have been at a disadvantage, often unaware of the specific tools used by the state. By providing a comprehensive "checklist" of technologies to inquire about, the ACLU is effectively raising the bar for what constitutes a thorough defense in the digital age.

Law enforcement advocates often argue that disclosing these methods would tip off criminals and render the tools ineffective. However, the ACLU maintains that in a democratic society, the government cannot use secret methods to deprive citizens of their liberty. As Jennifer Herrmann noted, the goal is to put "good lawyering" into the hands of every defense attorney, ensuring that the constitutional right to a fair trial keeps pace with the 21st-century surveillance state.

The toolkit is expected to be updated regularly as new technologies, such as car infotainment data siphoning and advanced biometric tools, become more prevalent in police work. The ACLU has requested that attorneys using the toolkit report back on their results, creating a feedback loop that will allow the organization to track which jurisdictions are most resistant to transparency and where new legal strategies are required.