Local Law Enforcement Borrow from NSA Playbook

Police departments around the country use cellphone data requests, called "cell tower dumps," to track and prosecute criminals.

by Kala Kachmar, McClatchy News Service / December 9, 2013

In 2006, the Montgomery Police Department used cellphone tower data to help convict a man who shot and killed a 30-year-old police officer in the head during a traffic stop.

Mario Woodward, 40, was charged with capital murder and then in 2008, sentenced to the death penalty by Montgomery County Circuit Judge Truman Hobbs. The officer, Keith Houts, left behind a wife and five children.

The case was the first time the Montgomery County district attorney's office obtained such data to use as evidence, according to District Attorney Ellen Brooks. Since then, the MPD has continued to use the method as an investigative tool.

All around the country, police departments are using cellphone data requests as tools to track and prosecute criminals.

In most places, police departments make requests to cellphone companies, through court orders or subpoenas, for information in the form of a "tower dump" or single cellphone tower data. Tower dumps are bulk records of customer activity of a specific tower for a specific period of time. Single cellphone data requests include all activity for a particular number, including location, calls, texts and other data usage.

Cell tower dumps are controversial because the data contains information on anyone's phone used within that area and time frame.

The Montgomery Advertiser made a public records request for any tower dump requests the city of Montgomery or MPD has made for tower dumps, including information on the provider name, the tower's federal ID and the date and time period covered by the dump requests.

The city, however, denied the request. A letter from City Attorney Jason Paulk said disclosing such information would "be detrimental to the best interest of the public."

"As you know, tower dump information requests are a vital law enforcement tool used by MPD and other law enforcement authorities," the letter said. "I do not think it would be wise for the general public, especially criminal elements, if this information shows up in the news to know how often, under what circumstances and for what time period MPD is using this law enforcement investigative tool."

The Advertiser also requested a blank form or sample request that these groups used to initiate a tower dump request, but Paulk said a blank form doesn't exist because requests are case-specific and vary in format.

MPD uses targeted requests to track missing people and find evidence for cases, but has never made a request for a tower dump, said Martha Earnhardt, a Montgomery public safety spokeswoman.

"There is no extraneous data," Earnhardt said. "It's all specific to a particular investigation and a particular suspect or suspects."

Montgomery County Sheriff D.T. Marshall said they also use cellphone tower data on occasion, but have never requested a tower dump either.

"It's a standard investigating tool," Marshall said. "It's not that often. This week it could be two or three, next month it might not be any. It just depends on the cases."

Police have to get a court order from a judge or a grand jury subpoena to take to cellphone companies for the information, Brooks said.

"Our office requires an active investigation and sufficient information that they have a legitimate reason to seek the information," Brooks said.

Brooks said to speed up the response to the request they try to draw the subpoena or court order as narrowly as possible. For example, if police are looking for evidence that someone was talking on a cell phone at the time a vehicle was wrecked, they would narrow the request to a reasonable amount of time.

Chief Deputy District Attorney Daryl Bailey said most of the single phone data requests ask for the call detail records in electronic format, with site and sector activation, with cell site addresses for the specific phone number for a specific period of time.

In the Woodward case, the cellphone tracking wasn't a critical part of the investigation, but it helped, Bailey said. He said the cell tower information was used by experts to corroborate Woodward's proximity to the crime scene, and the phone records were used to corroborate witnesses who testified he had spoken to them on that day at specific times.

He said there was other evidence that helped them get the conviction.

"What was crucial was trying to show the defendant was in a particular vehicle fleeing the scene of the crime," Brooks said.

Marshall said data alone isn't enough to convict someone. Several years ago, there was a double murder on Troy Highway, and information obtained from the cellphone companies afterward helped determine where the suspect was as they progressed away from the murder scene.

Brooks said unlike in movies and TV shows, they can't track people on their cellphones in real-time on a computer screen.

With a major murder case or a violent suspect on the loose, the district attorney's office can make an emergency request in a matter of minutes. But most requests take at least a day, and as long as weeks.

"You can imagine companies are inundated by these requests," Brooks said "We try to be very careful so when we really need it, we can get it. But it has proven to be a helpful investigative tool."

Brooks said police will review and analyze the records, and determine if the information helps their case. The district attorney's office just helps the police get the court order or subpoena.

"Sometimes they're helpful, sometimes they're not," she said. "It's part of the investigating file. If charges are brought, it's part of the file. If not, that's the end of it."

Bailey said the tool has evolved into a useful investigating tool over the years.

"It's an evolving process," Brooks said. "Every year, there's more technology and more availability of it. It's not as dramatic, nor as easy or informative. But one can get great leads and deductions from it."

Most requests are made for cases such as kidnappings, murders and sometimes robberies, Bailey said. And requests don't necessarily come across his desk every week, he added.

Bailey said he doesn't know that there's a specific law that addresses the ability to track cellphones, but it's not prohibited by law and it's not a constitutional violation.

The Advertiser also requested information that would indicate whether the city or police department uses an International Mobile Subscriber Identity (IMSI) locator device or program, which simulates a cellphone tower to obtain bulk cellphone data.

Paulk said the city doesn't have any such device or program in its possession.

"We don't generally go out and gather intelligence about (just) anything or anybody," said Chris Murphy, Montgomery's director of public safety. "It's limited to a specific investigation, suspect and the evidence related to that specific crime."

Murphy said if the MPD is involved with the use of special devices and technology, it's usually with the involvement of a federal agency.

"Yes, there are times when we have partnered with federal agencies and they have used equipment that is not in our arsenal or tool kit that have helped," Murphy said. "But we don't just go borrow their equipment or subpoena power."

(c) 2013 the Montgomery Advertiser (Montgomery, Ala.)