Most Americans carry cellphones, but many may not know that government
agencies can track their movements through the signals emanating from the handset.
In recent years, law enforcement officials have turned to cellular technology
as a tool for easily and secretly monitoring the movements of suspects as they
occur. But this kind of surveillance - which investigators have been able to
conduct with easily obtained court orders - has now come under tougher legal
In the last four months, three federal judges have denied prosecutors the right
to get cellphone tracking information from wireless companies without first
showing "probable cause" to believe that a crime has been or is being
committed. That is the same standard applied to requests for search warrants.
The rulings, issued by magistrate judges in New York, Texas and Maryland, underscore
the growing debate over privacy rights and government surveillance in the digital
With mobile phones becoming as prevalent as conventional phones (there are
195 million cellular subscribers in this country), wireless companies are starting
to exploit the phones' tracking abilities. For example, companies are marketing
services that turn phones into even more precise global positioning devices
for driving or allowing parents to track the whereabouts of their children through
Not surprisingly, law enforcement agencies want to exploit this technology,
too - which means more courts are bound to wrestle with what legal standard
applies when government agents ask to conduct such surveillance.
Cellular operators like Verizon Wireless and Cingular Wireless know, within
about 300 yards, the location of their subscribers whenever a phone is turned
on. Even if the phone is not in use it is communicating with cellphone tower
sites, and the wireless provider keeps track of the phone's position as it travels.
The operators have said that they turn over location information when presented
with a court order to do so.
The recent rulings by the magistrates, who are appointed by a majority of the
federal district judges in a given court, do not bind other courts. But they
could significantly curtail access to cell location data if other jurisdictions
adopt the same reasoning. (The government's requests in the three cases, with
their details, were sealed because they involve investigations still under way.)
"It can have a major negative impact," said Clifford S. Fishman,
a former prosecutor in the Manhattan district attorney's office and a professor
at the Catholic University of America's law school in Washington. "If I'm
on an investigation and I need to know where somebody is located who might be
committing a crime, or, worse, might have a hostage, real-time knowledge of
where this person is could be a matter of life or death."
Prosecutors argue that having such information is crucial to finding suspects,
corroborating their whereabouts with witness accounts, or helping build a case
for a wiretap on the phone - especially now that technology gives criminals
greater tools for evading law enforcement.
The government has routinely used records of cellphone calls and caller locations
to show where a suspect was at a particular time, with access to those records
obtainable under a lower legal standard. (Wireless operators keep cellphone
location records for varying lengths of time, from several months to years.)
But it is unclear how often prosecutors have asked courts for the right to
obtain cell-tracking data as a suspect is moving. And the government is not
required to report publicly when it makes such requests.
Legal experts say that such live tracking has tended to happen in drug-trafficking
cases. In a 2003 Ohio case, for example, federal drug agents used cell tracking
data to arrest and convict two men on drug charges.
Mr. Fishman said he believed that the number of requests had become more prevalent
in the last two years - and the requests have often been granted with a stroke
of a magistrate's pen.
Prosecutors, while acknowledging that they have to get a court order before
obtaining real-time cell-site data, argue that the relevant standard is found
in a 1994 amendment to the 1986 Stored Communications Act, a law that governs
some aspects of cellphone surveillance.
The standard calls for the government to show "specific and articulable
facts" that demonstrate that the records sought are "relevant and
material to an ongoing investigation" - a standard lower than the probable-cause
The magistrate judges, however, ruled that surveillance by cellphone - because
it acts like an electronic tracking device that can follow people into homes
and other personal spaces - must meet the same high legal standard required
to obtain a search warrant to enter private places.
"Permitting surreptitious conversion of a cellphone into a tracking device
without probable cause raises serious Fourth Amendment concerns, especially
when the phone is monitored in the home or other places where privacy is reasonably
expected," wrote Stephen W. Smith, a magistrate in Federal District Court
in the Southern District of Texas, in his ruling.
"The distinction between cell site data and information gathered by a
tracking device has practically vanished," wrote Judge Smith. He added
that when a phone is monitored, the process is usually "unknown to the
phone users, who may not even be on the phone."
Prosecutors in the recent cases also unsuccessfully argued that the expanded
police powers under the USA Patriot Act could be read as allowing cellphone
tracking under a standard lower than probable cause.
As Judge Smith noted in his 31-page opinion, the debate goes beyond a question
of legal standard. In fact, the nature of digital communications makes it difficult
to distinguish between content that is clearly private and information that
is public. When information is communicated on paper, for instance, it is relatively
clear that information written on an envelope deserves a different kind of protection
than the contents of the letter inside.
But in a digital era, the stream of data that carries a telephone conversation
or an e-mail message contains a great deal of information - like when and where
the communications originated.
In the digital era, what's on the envelope and what's inside of it, "have
absolutely blurred," said Marc Rotenberg, executive director of the Electronic
Privacy Information Center, a privacy advocacy group.
And that makes it harder for courts to determine whether a certain digital
surveillance method invokes Fourth Amendment protections against unreasonable
In the cellular-tracking cases, some legal experts say that the Store Communications
Act refers only to records of where a person has been, i.e. historical location
data, but does not address live tracking.
Kevin Bankston, a lawyer for the Electronic Frontier Foundation, a privacy
advocacy group that has filed briefs in the case in the Eastern District of
New York, said the law did not speak to that use. James Orenstein, the magistrate
in the New York case, reached the same conclusion, as did Judge Smith in Houston
and James Bredar, a magistrate judge in the Federal District Court in Maryland.
Orin S. Kerr, a professor at the George Washington School of Law and a former
trial attorney in the Justice Department specializing in computer law, said
the major problem for prosecutors was Congress did not appear to have directly
addressed the question of what standard prosecutors must meet to obtain cell-site
information as it occurs.
"There's no easy answer," Mr. Kerr said. "The law is pretty
Absent a Congressional directive, he said, it is reasonable for magistrates
to require prosecutors to meet the probable-cause standard.
Mr. Fishman of Catholic University said that such a requirement could hamper
law enforcement's ability to act quickly because of the paperwork required to
show probable cause. But Mr. Fishman said he also believed that the current
law was unclear on the issue.
Judge Smith "has written a very, very persuasive opinion," Mr. Fishman
said. "The government's argument has been based on some tenuous premises."
He added that he sympathized with prosecutors' fears.
"Something that they've been able to use quite successfully and usefully
is being taken away from them or made harder to get," Mr. Fishman said.
"I'd be very, very frustrated."