OAKLAND, Calif.—At a Monday hearing in federal court, US Magistrate Judge Donna Ryu had strong words for prosecutors in an attempted murder and gang case that has dragged on for nearly three years.

"It is stunning to me that at this point in the case, the government cannot tell me very clearly what search has been done and what exists or does not exist, relevant to a stingray," she said with exasperation.

As Ars reported over a year ago, the case of United States v. Ellis et al involves four men who are charged with the 2013 attempted murder of local police officer Eric Karsseboom. The men are also charged with running an alleged East Oakland gang centered around Seminary Avenue (known as "SemCity").

But in the process of locating lead defendant Purvis Ellis on the night of January 21, 2013, the Oakland Police Department may have unintentionally opened up a way to challenge evidence in the case. How? Due to the warrantless use of a stingray, or cell-site simulator.

Since Ars last reported on the story, the government has admitted in court filings earlier this year that, not only did the Oakland Police Department have a stingray at the scene, so did the FBI.

Stingrays can be used to determine a mobile phone's location by spoofing a cell tower. In some cases, stingrays can intercept calls and text messages. Once deployed, the devices intercept data from a target phone along with information from other phones within the vicinity. At times, police have falsely claimed the use of a confidential informant when they have actually deployed these particularly sweeping and intrusive surveillance tools.

As lawmakers have scrutinized stingrays over the last year, policies requiring a warrant for stingray use have been handed down by several federal agencies and state governments, including the Department of Homeland Security, the Department of Justice, and the state of California. These policies, however, were not in place during the Oakland shooting in question three years ago.

During the Monday hearing, Judge Ryu ordered that the government must complete a formal declaration to the court that would explain, in as much detail as possible, exactly how the stingrays were used. She has given them two weeks to comply.

Slow-moving discovery

The entire stingray issue has been brewing since February 2015, when two of the defense team's lawyers, Martha Boersch and Christopher Cannon, filed a disclosure motion . The attorneys asked the court to require the government to say whether electronic surveillance had been used. The government's response came in April 2015 and claimed that no warrant was required, as there were "exigent circumstances."

According to American criminal procedure law, an exigent circumstance involves imminent bodily harm or injury, the destruction of evidence, or the flight of a suspect. In such situations, law enforcement officers do not require a warrant.

Since April, the defense has dug deeper for further discovery related to the stingray issue, but the government has resisted. The two sides have met privately in what's dubbed "meet and confer," and they have also reported back to US Magistrate Judge Ryu before returning to the case's primary judge, US District Judge Phyllis J. Hamilton. While the case has ping-ponged between the two judges for much of the last year, the stingray issue still remains unresolved, as do many other issues in the case. No trial date has been set.

In February 2016, the defense asked for 29 categories of discovery, which were eventually whittled down to 16. By April 2016, prosecutors pushed back even harder by arguing that "balancing the public interest against the defendant's stated need for discovery weighs strongly against disclosure here."

To that end, the government included two declarations asserting the need for secrecy. The first is a generic explanation from William Chapman, the FBI’s top stingray official, declaring that stingray information should not be disclosed because it is "law enforcement sensitive."

The other declaration, filed by an Oakland police officer who was present for the January 2013 shooting and whose name was redacted, states:

Pursuant to standard practice, after the location operation, OPD did not retain any information captured by the device, including the electronic serial numbers (or their equivalent) from wireless devices in the immediate area that may have been incidentally recorded, including those of non-target devices. This information is deleted after every operation.

The government wants to allow the OPD officer and possibly an FBI official to testify before the judge in a closed-door, ex parte (one-sided) hearing in which the defense would not be present.

During the Monday hearing, Boersch, herself a former federal prosecutor, said that it’s still not clear "when the stingray got" to the East Oakland apartment where OPD Officer Karsseboom arrived on the night in question.

"It's important for the defense to know who got there and who was calling who," she said. "Witness who would say they were called by OPD—how OPD got their numbers, we don’t know."

She said that Ellis' phone was turned off and inactive as of 8pm.

"If OPD or FBI were using that stingray solely to locate Mr. Ellis on that phone, it could not have happened, as the phone was inactive," Boersch continued.

The judge responded: "I don’t know how the stingray operates with respect to when there's a quote 'inactive' phone."

"My understanding is that the phone was off, so I don't know how [the stingray] could have picked anything up," Boersch added. "The stingray, moreover, it picks up all phones, not just Mr. Ellis'. Clearly they're picking up who is calling who on what numbers and when, and I think that is material under the case law that we've cited."

Scott Joiner, a DOJ prosecutor, told the judge that the department has asked for official FBI "302" files, but that "there were none generated."

"Stunned"

As the back-and-forth continued, Judge Ryu became noticeably irritated.

"When I see the word 'deployment log' or 'records of use,' I'm picturing a record that would say when the cell-site simulator was on site, maybe how it was deployed, when it was turned on, what it was looking for, anything that shows what it was capturing, anything that shows later what was purged," she told Joiner.

"I do not think that exists, Your Honor," Joiner responded.

"So this is what is kind of stunning to me," she said, turning to the most-high profile stingray case that has been previously litigated, US v. Rigmaiden. (The defendant in that case, an accused tax fraudster named Daniel Rigmaiden, was released from prison in 2014.)

"In Rigmaiden, that judge went through a comprehensive review of materials, some was part of ex parte, but what's stunning was how much info the government turned over without blinking an eye. I'm seeing this US Attorney’s office take a very different view. If what you're saying, Mr. Joiner, is it's all a deep secret, even what papers exist that might say anything about what was kept on stingray use, I'm pretty stunned."

"That's a mischaracterization of what I said," Joiner responded. "I do not believe deployment logs exist. The technological specifics of how [the stingray is] configured are protected, and they were protected under Rigmaiden."

The judge didn't miss a beat.

"There's information right now that says [the stingray is] configured like a pen register or a trap trace—it doesn't pick up content," she pressed. "So obviously something regarding configuring can be said on the record. Was it looking for certain numbers? If so, what were those numbers? Was it Mr. Ellis' number?"

"We've already said that—it was configured to look for Mr. Ellis' number," he replied.

"I don't think so," Ryu retorted.

"I will make a representation right now," he said.

Joiner was, in fact, correct. The government said in a March 2016 filing that the stingray was only used to locate Ellis and his phone.

"I am getting frustrated," Judge Ryu continued. "This has gone on for so long. What I want to see happen—is that the defense is entitled to personal knowledge declarations. If you need to redact a name—I doubt the defense will object—you deal with names later."

Unlike the declaration from the FBI's William Chapman, personal knowledge declarations would have to come from people who had direct knowledge of the January 21, 2013 Oakland shooting and its aftermath.

Judge Ryu continued:

But they should be personal knowledge detailed declarations that explain when this simulator was brought on site, who brought it, what time, what time it was turned off, how it was operated. Was it moving around in a car? [The declaration] should say whether [the stingray] was configured to pick up certain numbers. Was it configured to look for Ellis or any other particulars? If it was purged, when was it purged? Why was it purged? Is it pursuant to a policy? What is the policy? Who purged it? That's just the basic who, where, what, when, why, how. Otherwise, [the defense] get[s] to know this. I'm going to order that the US Attorney provide a declaration to the defense saying that they have made all inquiries to OPD, to FBI, or any other responding party reasonably known and have found no documents that indicate anything about use of a stingray. I'm going to give you two weeks, because this has been hanging out too long.

Before the judge turned her focus to other pending issues in the case, she had one final warning for the prosecutors.

"The government had better be very careful, because I don't want an over-claiming of the [law enforcement] privilege. If there are materials out in the world as to how [stingrays] are used, [those materials are] not a secret," she said. "Please be judicious in your application of that privilege."

The two sides are set to meet again for a status conference before US District Judge Hamilton on August 24.