A recent Massachusetts federal court decision marks a significant development in Fourth Amendment law and digital privacy, particularly for cases involving so-called “cell tower dumps.”
The Case: United States v. McDonald
In United States v. McDonald, U.S. District Court Judge Patti B. Saris considered whether a “tower dump” — the collection of cell site location information (CSLI) from every device that connected to certain cell towers during a specific time window — constitutes a search under the Fourth Amendment.
The case arose from an armed robbery of a cash courier in Swansea, Massachusetts. Law enforcement suspected that the perpetrators used cell phones to coordinate the crime and escape. Investigators obtained warrants compelling three cellular service providers to turn over CSLI for all devices that communicated with four cell towers near the robbery scene and related locations over roughly an hour.
Those warrants ultimately swept in data associated with approximately 14,000 devices, the vast majority of which belonged to individuals with no connection to the crime.
The defendant, Quentin McDonald, moved to suppress the CSLI evidence, arguing that:
- A tower dump is a Fourth Amendment search requiring a warrant; and
- The warrants issued were unconstitutional “general warrants” lacking sufficient particularity.
The Court’s Ruling
Judge Saris agreed with the defense on their point that tower dumps do constitute Fourth Amendment searches.
Relying on the Supreme Court’s landmark 2018 decision in Carpenter v. United States, the court held that even short-term CSLI raises serious privacy concerns. As the court noted, tower dumps can reveal intimate details about a person’s movements and associations, which may include visits to private homes, medical offices, political organizations, and other sensitive locations.
The court ultimately denied the motion to suppress, as Judge Saris ruled that the warrants in this case were sufficiently narrow in time, place, and scope, identifying specific towers, limited time windows, and defined categories of non-content data. Even if the warrants had fallen short, the court held, the good-faith exception to the exclusionary rule would have saved the evidence because the law in this area remains unsettled.
Why the Decision Matters
Although the defendant did not prevail, McDonald is widely viewed as an important Fourth Amendment landmark. Many courts have avoided ruling that tower dumps are searches at all. This decision squarely recognizes that mass digital location sweeps trigger constitutional protections, and that checks and balances are still available to limit dragnet surveillance. [— a key step in limiting dragnet surveillance.]
At the same time, the ruling highlights an ongoing frustration for the defense bar: courts often acknowledge constitutional violations in theory, only to deny meaningful remedies in practice through the good-faith doctrine.
Attorney Vikas Dhar: “This Shifts the Fight”
In an article in Massachusetts Lawyers Weekly, Attorney Vikas Dhar emphasized that the decision fundamentally reframes how these cases will be litigated:
“The question going forward isn’t whether police need a warrant, but whether the warrant is sufficiently narrow in time, place and scope to avoid becoming a digital general warrant,” he said.
“Law enforcement largely prevailed here because the warrants were carefully engineered and because the law is unsettled. That good-faith cushion will shrink as more courts weigh in.”
His analysis highlights the real takeaway from McDonald: law enforcement can no longer assume that broad cell-phone data collection escapes constitutional scrutiny. As more courts address tower dumps and related techniques like geofence warrants, the margin for error will narrow and warrants that resemble digital fishing expeditions may no longer survive.
Looking Ahead
The Supreme Court has already agreed to hear Chatrie v. United States, a case involving geofence warrants, signaling that location-based surveillance remains an active and evolving area of constitutional law. Decisions like McDonald suggest that while courts may allow evidence from tower dumps today, the rules governing digital searches are tightening.
For defendants and defense attorneys, the message is clear: the future fight will focus on overbreadth, particularity, and proportionality and whether modern warrants respect the Fourth Amendment’s core purpose of preventing general searches.
At Dhar Law, LLP we work tirelessly to hold law enforcement accountable and to defend the constitutional rights of our clients in court. Contact a member of our award-winning criminal defense team at 617 880-6155 to learn more about how we can support you.
