Cell Site Technology

This undated handout photo provided by the U.S. Patent and Trademark Office shows the StingRay II, manufactured by Harris Corporation, of Melbourne, Fla., a cellular site simulator used for surveillance purposes. (AP Photo/U.S. Patent and Trademark Office)

ST. LOUIS • A defendant’s push for details about a cellphone tracking device used to investigate him was cut short Thursday with a plea agreement that dropped five of his six charges.

As part of the deal, Melvin Dante Hardy received a five-year term for being a felon in possession of a firearm. The defense dropped challenges to the use of the sophisticated tracker, whose full capabilities have been kept secret.

An earlier plea deal offer was for 12 years in prison, his lawyer said.

At the time of his arrest in January 2014, Hardy, of St. Louis, was sought on an arrest warrant stemming from a probation violation and in another investigation. He was convicted in St. Louis Circuit Court, and in 2015, he was indicted on federal drug and gun charges.

His challenge of the tracking technology was the latest in the St. Louis area, and had progressed the furthest.

Secret Service Special Agent Dan Doyle gave detailed testimony Aug. 30 about how investigators use the device, known by the name of a commonly used version, StingRay. It mimics a cellphone site to find a particular phone by its unique identifying number.

But Doyle refused to disclose information about the model or the manufacturer, citing a nondisclosure agreement.

In a Sept. 8 hearing, U.S. District Judge John Ross, presiding over Hardy’s case, was skeptical about the need to keep secret the manufacturer, make and model. He repeatedly asked Assistant U.S. Attorney Cristian Stevens to give him the “compelling government interest” for it.

The judge postponed the trial to give prosecutors and defense lawyers time to respond. On Tuesday, prosecutors received a delay until Friday to comply with Ross’ demand. Later Tuesday, Hardy’s plea hearing was scheduled for Thursday.

Diane Dragan, one of his lawyers, also was seeking a host of other information about how the trackers operate, and how law enforcement uses them. In the Aug. 8 hearing, Ross said that her requests were “incredibly overbroad” and that it seemed like she was “on a mission for information that can be used in other cases.”

Stevens has argued that release of that information could allow the targets of investigations to circumvent those techniques.

Some prosecutors around the country have dismissed cases rather than reveal information about the technology, even though its use and some of its capabilities have been publicly reported. More is surfacing as the devices are more widely used — and more widely challenged.

On Monday, an online site, the Intercept, published leaked manuals for StingRay trackers, which suggest that some versions can store and search photo data.

In Hardy’s case, Doyle said that the device is incapable of storing any data. That tracker is no longer in use, and the Secret Service was having trouble finding it, Stevens has said.

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