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Cell-site tracking information: Do police need a warrant?

Oct 13, 2018 | Criminal law

Remember back to when mobile phones required a glove box or center console in the car? Today, these mini computers fit in our pockets and go almost everywhere with us. Cellular phones are rarely even used for calls anymore.

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The law, however, does not move at the speed of technology. For years, law enforcement agencies – federal DEA agents to local police – have asked phone carriers for cell tower records to find out where possible suspects have been. The U.S. Supreme Court in the Carpenter v. U.S. case weighed in on the issue. And it said, yes, a warrant is required to support these requests.


An armed robbery conviction based on cell-site records

How did the case get to the Supreme Court? A conviction for armed robberies in Ohio and Michigan and a sentence of 116 years in prison. The investigation hinged on cell-site records that placed the suspect nearby when the crimes occurred.

Carpenter asked that the court exclude the records in his jury trial, because law enforcement never got a warrant. Holding that he had no expectation of privacy in the records, the trial court denied his request. A federal appeals court upheld that decision.

A divided Supreme Court ruling

In a 5-4 decision, the U.S. Supreme Court reversed in part because of “seismic shifts in digital technology.” The ruling is narrow and may allow police to obtain day-of location information or in emergencies like child abductions without first seeking a warrant.

Two questions were important: Did Carpenter have an expectation his whereabouts were would be kept private? Was this a garden-variety third-party records request?

Answering the first, Chief Justice John Roberts mentioned that most people would not expect police to be tracking their movements over long chunks of time. Tracking movements via cell signal could be analogized to an ankle monitor and the records can go back up to five years.

On the second question, the seismic shifts in technology and “unique nature” were enough to take these record requests out of the garden variety column. Because the third-party doctrine didn’t apply, the government generally must obtain a warrant.

Lengthy dissents

What was unusual in this case, was that each of the dissenting justices wrote lengthy opinions. The concerns varied from the creation of a “crazy quilt” of Fourth Amendment law to a suggested property interest standard rather than the “reasonable expectation of privacy.”

This case highlights how omissions (failing to request a warrant) in an investigation can violate Fourth Amendment rights. It often takes an experienced criminal defense attorney to identify these rights violations and fight to correct them.