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Tracking a User's Location via Cell Phone

Nov 16, 2006
Daniel R. Sovocool and Kristin Jamberdino

Privacy Implications

page 1 of 3

A hot issue currently being debated in the courts involves the intersection of privacy law and technology: the ability to use cellular phone signals to track the location of users. As communications technology grows more powerful, it becomes easier to collect information on consumers that subscribe to services such as cell phone providers and GPS locators, which require constant interaction with towers or satellites. The government has seized upon the ability to track people using this electronic data in order to strengthen its investigatory practices.

The argument for easy access to such information is that particularly in the age of increased awareness of and sensitivity to the potential for domestic terrorism, knowing the location of possible perpetrators is crucial to uncovering and shutting down criminal activity as quickly as possible. However, the high potential for abuse of the privacy rights of individuals that use these services is serious enough that the Department of Justice has been taken to court repeatedly in recent months, in order to determine just where the line between legitimate investigation and protection of privacy should be drawn.

The purpose of this article is to discuss recent cases that address the standard that courts have placed upon investigators to procure real-time tracking information from data communications companies.

For a cellular phone to readily receive calls there must be continuous communication between the physical phone and the service provider’s satellite towers. This signal can be used by phone companies to track the whereabouts of individuals. Developing technology coupled with an increasing number of cell sites built to handle the rapidly expanding cell phone market have led to increased accuracy in triangulating the physical location of a user. A useful tool for locating 911 callers from their cell phones,1 the service can be used to track any individual with a cell phone that is powered on, regardless of whether or not the user is engaged in a call.

Law enforcement officials have long used data stored by cell phone service providers to track individuals suspected of committing crimes, but no statute clearly sets out the standard for what evidence is needed before court-ordered disclosure of this information may be granted. Recently a number of decisions have been passed down discussing cell phone tracking and the standard by which law enforcement officials may request data to locate an individual via their cell phone. Of the six decisions handed down (from the Eastern District of New York, Southern District of Texas, District of Maryland, Southern District of New York,

District Court for the District of Columbia and Eastern District of Wisconsin),2 four ruled that a search warrant based on probable cause is required before law enforcement can track someone’s location using cell phone data.3 Although judges have urged the Department of Justice to appeal the rulings so that a uniform standard can bring clarity to the issue, the DOJ has declined to do so. The lone case rejecting probable cause as the required standard was handed down in December 2005 from the Southern District of New York.4

The issue raised in these cases is whether "real-time" cell site information that locates a user, regardless of whether or not they are engaged in a call, requires a different burden than requesting pen register information (a record of outgoing calls from a particular number) or trap and trace information (a record of incoming calls to a particular number). In the absence of legislation regarding cell site tracking information, the government has argued that a combination of two statutes provides the right to request such information at a standard lower than probable cause: the Stored Wire and Electronic Communications and Transactional records Access Act ("SCA"), 18 U.S.C. § 2701 et seq., and 18 U.S.C. § 3121 et seq. (the "Pen/Trap statute"). The SCA gives the government access to "a record or other information pertaining to a subscriber to or a customer of such service (not including the contents of communications)."5 The government can access this information via court order if it "offers specific and articulable facts showing that there are reasonable grounds to believe that…the records or other information sought are relevant and material to an ongoing criminal investigation."6 Because the SCA refers to records of calls completed, not real-time tracking data such as the information the government has sought to obtain, this cannot be the sole statute under which the government seeks information disclosing the physical location of its targets.7

In order to obtain authorization for installation of a pen register and trap/trace device under the Pen/Trap statute, the government must only assert that the information requested is "relevant to an ongoing criminal investigation."8 The government argues that the USA PATRIOT Act of 20019 now includes real-time cell site information within the definitions of both "pen register" and "trap and trace device."10 The consequence of that expansion is under debate, because in 1994 Congress amended the SCA by passing the Communications Assistance for Law Enforcement Act ("CALEA").11 CALEA prohibits the disclosure of "any information that may disclose the physical location of the subscriber" when the government seeks such information "solely pursuant to the authority for pen registers and trap and trace devices."12 The government asserts that by working pursuant to both the SCA and the Pen/Trap statute, it has the right to obtain such information without probable cause or a search warrant. Four courts have rejected this, stating that as the SCA does not refer to real-time data, and the Pen/Trap statute gives no right to information tracking a user’s location, the only way to grant the government access to such information is under Federal Rule of Criminal Procedure 41(d)(1), which requires a showing of probable cause before a search warrant is issued.13

The government has also argued that there is no Fourth Amendment implication in the communication between the cell phone and a cell tower. Thomas Brown, the Assistant U.S. Attorney who ran the case in the Southern District of New York, asserted in court documents that a "cell phone user voluntarily transmits a signal to the cell

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