Digital Bread Crumbs: Following Your Cell Phone Trail
NPR's Martin Kaste holds a GPS-enabled iPhone and a Blackberry that relies on cell phone data. - The iPhone, in Martin Kaste's left hand, has its GPS enabled, and it knows exactly where it is. The BlackBerry in his right hand is relying only on cell tower data, which means the mapping software isn't showing you where the phone is — it's showing you where the nearest tower is. In this case, just a couple of blocks away. (Alyson Hurt/NPR)
Third in a four-part series
Jeff Fischbach is a little bit like those guys in The Matrix — when he puts on his shades and looks at the world, he sees data.
Walking down the street in San Francisco, he points out all the devices that record people's comings and goings: digital parking meters, apartment intercom systems, digital security cameras.
(Martin Kaste/NPR)
"Anything with a computer is going to keep a log," Fischbach says.
Fischbach is a forensic technologist. Lawyers eagerly pay for his ability to extract evidence from everyday devices — he's even checked alibis on kitchen appliances. But when it comes to tracking where people go, he says, the most common source of data is in your pocket.
"Cell phones leave a data trail," he says. "And it's becoming standard for major police departments and the feds to use this data." (Story continues after the gallery.)
Finding Your Location
Fischbach says he has worked on at least 250 criminal cases that relied on cell phone data. It's almost unusual to find prosecutors who don't check cell phone records, he says.
"More and more I'm finding that it's being used as the sole evidence in a case," Fischbach says. "That concerns me a little bit."
Fischbach will work for the prosecution or the defense.
At a meeting with Robert Amparan, a San Francisco lawyer defending a young man charged with a gang-related homicide, Fischbach helps to make sense of a sheaf of printouts from a local cell phone company. It is data from the cell phone towers that prosecutors are using to place the defendant at the scene of the shooting.
Fischbach is here to translate the codes and to provide the defense with some reasonable doubt.
"They can't say he was here," Fischbach tells the lawyer. "What they can say is he could have been at the crime scene. That cell sector covers the crime scene."
The location is vague because this phone relies only on tower data — that is, the records of which cell tower the defendant's phone was connecting through and from which angle. Depending on the density of the tower network, the margin of error can be as much as a couple of miles.
But that margin is shrinking.
Newer phones come with optional GPS, the satellite-based location service, which users can choose to turn on, though at a considerable cost to battery life.
Even with the GPS off, phone location is getting more precise. Some phones use more than one tower to triangulate their locations. Others "find" themselves by locating nearby Wi-Fi signals and checking them against a master catalog of Wi-Fi signals with known coordinates.
While location data aren't enough to prove guilt or innocence, they can be very useful to investigators. Police can find potential witnesses. Employers can double-check mileage claims on an expense report.
Looking At Your Location
So the big question is, who gets to see these records?
Fischbach says, "It's really all over the map."
When it comes to requests for tower data, he says, some cell companies just require subpoenas. Others require warrants, which presuppose a probable cause and the involvement of the court.
Sometimes, Fischbach says, all it takes is a little charm.
""I even managed to get that sort of information for a defendant recently just by calling up and speaking to someone who was pretty friendly," he says.
Real-time tracking requires a warrant — the courts have settled that — but there's a lot less certainty about the privacy of the records of where a cell phone has been.
Jennifer Granick, the civil liberties director at the Electronic Frontier Foundation, calls the situation a "mess." The federal law covering cell phone location records is out of date and overly complex, Granick says.
"Normal people can't understand it, defense attorneys can't understand it, a lot of judges can't understand it, and really, when you drill down, it doesn't make a lot of sense," she says.
Federal law puts a lot of importance on esoteric, technical details. For instance, the privacy of the records often depends on which technology was used to calculate the phone's location.
"It doesn't seem, I think, to the average cell phone owner that there should be a big difference," Granick says. "But because of the technological way that people can get access to your location information, the law, surprisingly, treats them very differently."
And this leads to uncertainty for law enforcement, too.
Expectation Of Privacy?
In theory, detectives could get a quick list of potential witnesses by requesting the numbers of all the phones using a certain tower at a given time. But few departments take advantage of this tool. That's because it sometimes takes too much effort to sift through that many names and numbers.
But it's also because courts haven't settled whether that kind of digital dragnet is acceptable. Oklahoma County, Okla., First Assistant District Attorney Scott Rowland is one prosecutor who says it is. Rowland says people in public places don't have any more expectation of privacy for their phone location than they do for their car's presence at the shopping mall.
"Police can go up and down the row and take tag numbers and run them to see who's at the mall," Rowland says. "You don't have an expectation that others won't see you there."
Rowland gives seminars to fellow prosecutors on how to use phone data. He tells them they don't need a warrant for tower data, but he says they should probably get one, anyway, because the law is still so unsettled.
"It's a little surprising to me that the federal courts have been in my opinion a little bit slow to take on one of these head-on and resolve the issue," Rowland says.
There is a case pending in the 3rd U.S. Circuit Court of Appeals that some experts believe will help define the privacy protections for cell tower location records.
Finding Your Friends On A Map
Meanwhile, phone location is becoming an ever more visible part of everyday life.
"A person's location is a great conversation starter," says Steve Lee, the product manager for Google Latitude. It's one of several competing services that allow people to share their location with friends.
Lee says phone location services are a social tool, good for finding friends in a crowd, or colleagues at a conference. The service is free; Lee says Google hopes to make money from an increase in Web searches by people using the location service on their smart phones.
Lee says the company may also experiment with ads tailored to a phone's location.
Right now, Google is going slowly, limiting what the tracking software can do. For instance, Latitude does not keep a record of where users have been, even though Lee says that data would be "very valuable."
Lee says phone location tracking is something that strikes some people as "cool but creepy."
"Over time, people will become more and more comfortable with it," he says. "But not everyone's going to be comfortable with this, and they don't need to share their location with other people."
Fischbach, the forensic technologist, is in the "cool but creepy" camp. He's creeped out by what his own phone can do.
"I walked around my own house, and it's not a mansion, and I could see on the phone where I was standing in the house," he says, adding that he usually keeps the GPS option switched off.
At the same time, Fischbach welcomes the arrival of services like Google Latitude and a similar platform called Loopt. He says all they're really doing is making visible the kind of data that he sifts through for a living. And he says it's probably good that people start seeing the trail of digital bread crumbs that they've been leaving all along.
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ROBERT SIEGEL, host:
This is ALL THINGS CONSIDERED from NPR News. I'm Robert Siegel.
MELISSA BLOCK, host:
And I'm Melissa Block.
The cell phone in your pocket is a tracking device. And with the addition of GPS, it's getting more exact. Prosecutors and private investigators have come to depend on this information, but the law is fussy about who is really entitled to see your cell phone trail.
NPR's Martin Kaste reports as part of our series The End Of Privacy.
MARTIN KASTE: Jeff Fischbach is a little bit like those guys in "The Matrix" — when he puts on his shades and walks down the street, he sees data.
Mr. JEFF FISCHBACH (Forensic Technologist): We have digital meters that monitor when a car moves and resets themselves. We just passed a intercom system that's going to go through a computer. Anything that runs through a computer is going to keep a log. And…
KASTE: Fischbach is a forensic technologist. Lawyers eagerly pay him for his skill in extracting evidence from everyday devices. He's even checked alibis on kitchen appliances. You know that lie you told in your divorce trial? Your coffee maker may rat you out. But Fischbach's bread and butter is cell phones. These days, phone data are the foundation of many a prosecution.
Mr. FISCHBACH: It's been pretty standard the last couple of years. More and more often I'm finding that it's being used as the sole evidence in a case. That concerns me a little bit.
KASTE: He's worked on at least 250 criminal cases involving cell phones. Today he's at the office of San Francisco defense attorney Robert Amparan, who's got a client facing a murder charge.
Mr. ROBERT AMPARAN (Defense Attorney): A gang-related shooting that occurred at corner of Turk and Gough on March 20th, 2008 at about 8 p.m.
KASTE: On the conference table between them is a sheaf of printouts from the local cell phone company. It's the tower data that prosecutors are using to place the defendant at the scene of the crime. Fischbach is here to translate the tower codes and to provide the defense with some reasonable doubt.
Mr. FISCHBACH: What they can reasonably say - they can't say he was here - what they can say is he could've been at the crime scene. That cell sector covers the crime scene.
KASTE: Fischbach regards this kind of tower data as corroborating evidence, something you can use to check someone's story. Still, these data are very valuable for investigators looking for leads or witnesses. So, the big question is: Who gets to see them?
Mr. FISCHBACH: It's really all over the map.
KASTE: Fischbach says some cell companies just require subpoenas, while others want signed warrants. Sometimes all you need is a little charm.
Mr. FISCHBACH: I even managed to get that sort of information for a defendant recently just by calling up and speaking to someone who was pretty friendly.
KASTE: Strange that may seem, here we are two decades into the cell phone era and the rules are still unclear. Real-time tracking does require a warrant. The courts have settled that. But when it comes to the history of where you've been…
Ms. JENNIFER GRANICK (Civil Liberties Director, Electronic Frontier Foundation): It's a mess.
KASTE: Jennifer Granick is a lawyer and civil liberties director at the Electronic Frontier Foundation. She says federal law is out-of-date and overly complex.
Ms. GRANICK: Normal people can't understand it. Defense attorneys can't understand it. It's hard, you know, it's hard for judges to understand it. And it really, when you kind of drill down, doesn't make a lot of sense.
KASTE: Part of the problem, she says, is that the law puts a lot of importance on esoteric, technical details. For instance, the method of calculating your phone's location, whether it's GPS, tower data or some other method can actually affect your privacy rights.
Ms. GRANICK: It doesn't seem, I think, to the average cell phone owner that there should be a big difference. But because of the technological way that people can get access to your location information, the law, surprisingly, treats them very differently.
KASTE: And this leads to uncertainty for law enforcement, too. In theory, phone records are a great way for police to find everybody who is near a crime scene. But only some departments take advantage of this tool. That's partly because it takes a lot of man hours to sift through that many names and numbers. But it's also because the courts haven't settled yet whether that kind of digital dragnet is acceptable. Oklahoma City First Assistant District Attorney Scott Rowland is one prosecutor who says it is.
Mr. SCOTT ROWLAND (First Assistant District Attorney, Oklahoma City): I don't believe you have any more expectation of privacy in not having your phone number obtained in a cell data dump like that, then you do when you go to the shopping mall. The police can go up and down the row and take tag numbers and run and see who's at the mall. You're at the mall. And you don't have an expectation that other folks won't see you there.
KASTE: Rowland gives seminars to fellow prosecutors on how to use cell phone data. He tells them that they don't need a warrant for tower data, but he says they might want to get one anyway, just in case, because the law is still so unsettled.
Mr. ROWLAND: It's a little surprising to me that the federal courts have been, in my opinion, a little bit slow to take one of these head-on and decide the issue.
KASTE: There is a case pending in the 3rd Circuit Court of Appeals that many experts believe will eventually help to define the privacy protections for phone location. And it can't come too soon as GPS is now making phone location more precise and part of everyday life.
Mr. STEVE LEE (Product Manager, Google Latitude): A person's location is a great conversation starter.
KASTE: Steve Lee is group product manager for Google Latitude, one of the many services that now let you share your phone location with friends. He calls it a social tool.
Mr. LEE: I went to Washington, D.C. in January for the Obama inauguration. And a friend of mine, Sarah(ph), who lives in London, I noticed on Latitude was also in Washington, D.C. at the same time.
KASTE: So, it's great for finding friends in a crowd. It could also be big business, at least that's Google's hope, as it explores ways to offer people location-based advertising. Still, the company is going slow, purposefully limiting what Latitude can do. Lee says some people need time to ease into all of this.
Mr. LEE: Some people describe it as cool, but creepy. So, I think over time people will become more and more comfortable with it. But it's the kind of thing, you know, not everyone's going to be comfortable with this, and they don't need to share their location with other people.
KASTE: Our forensic technologist, Jeff Fischbach, is one of those who believe it's cool, but creepy. He's a little creeped out by what his own new smartphone can do.
Mr. FISCHBACH: Let me tell you how precise mine is and why, outside this interview, I won't be leaving it turned on. I walked around my own house, and it's not a mansion, and I could see on the phone where I was standing in the house.
KASTE: At the same time, he welcomes the arrival of services like Google Latitude. He says all these services are really doing is making visible the kind of data that he sifts through for a living. And it's probably a good thing for people to start seeing the trail of digital bread crumbs that they've been leaving all along.
Martin Kaste, NPR News.
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BLOCK: To test just how precise the new GPS enabled phones are, Martin and his editor took two phones, one with GPS and one without, on a tour of Los Angeles landmarks and compared their accuracy. You can see the results and hear the other stories in this series at npr.org. Transcript provided by NPR, Copyright National Public Radio.
