Cellular Location Site Information (CLSI) allows law enforcement, through the global positioning system (GPS) and phone company records, to track the location of a cellphone anywhere in society or even in one’s own home.


CLSI played a major role in investigating the University of Idaho murders case that began in the early morning hours of November 13, 2022, with the brutal murder of four university students in an off-campus apartment in the small community of Moscow, Idaho.


The case drew intense national and international media attention as state and federal law enforcement agencies investigated the crime. 


In late November, a Washington State University criminal justice student, Bryan Kohberger, became a suspect in the crime through video surveillance of a vehicle similar to one owned by the suspect and through an eyewitness statement and DNA evidence.


On December 23, 2022, law enforcement authorities sought and secured a search warrant for AT&T records of a cell phone they believed belonged to Kohberger. Cell phone data collected from that search placed Kohberger’s phone at or near the crime scene on the date that the crime occurred and nearly a dozen other times near the crime scene during the three months preceding the crime.


This CLSI evidence will undoubtedly be a contested issue at Kohberger’s trial. 


CLSI is gathered through a technique called triangulation—a process of using GPS data from multiple cell towers to locate a cell phone’s location. The method is reportedly accurate within five to ten feet.


However, the jury is still out on the forensic value of CLSI evidence. Envista Forensic reports that:


More stories all over the media highlight the errors coming to light with cell phone location evidence. For example, an article in The New York Times states that over 10,000 court verdicts are under review in Denmark due to the Danish authorities’ improper analysis of cellular call detail records. The article says, “The first error was found in an IT system that converts phone companies’ raw data into evidence that the police and prosecutors can use to place a person at the scene of a crime. During the conversions, the system omitted some data, creating a less-detailed image of a cellphone’s whereabouts. The error was fixed in March [2019] after the national police discovered it. In a second problem, some cellphone tracking data linked phones to the wrong cellphone towers, potentially connecting innocent people to crime scenes.” 


CLSI also has a history, Envista Forensics reports, of linking cell phones to the wrong masts, connecting them to several cell towers simultaneously that are hundreds of miles apart, recording text messages wrongly, and/or getting the location of specific towers wrong.


These errors come occur when phone companies like AT&T use automated software to analyze CLSI rather than have the evidence verified by a qualified expert.


Another key legal issue in the Kohberger CLSI evidence is whether law enforcement had established sufficient probable cause to support the CLSI search warrant. 


The U.S. Supreme Court in 2017 in Carpenter v. United States held that law enforcement will almost always need a search warrant supported by probable cause to access CLSI evidence.


In an opinion delivered by Chief Justice John Roberts, supported by four other justices, the Court laid out in some detail the specific legal concerns about CLSI evidence:


“A person does not surrender all Fourth Amendment protection by venturing into the public sphere. To the contrary, ‘what [one] seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.’ A majority of this Court has already recognized that individuals have a reasonable expectation of privacy in the whole of their physical movements. Prior to the digital age, law enforcement might have pursued a suspect for a brief stretch, but doing so ‘for any extended period of time was difficult and costly and therefore rarely undertaken.’ For that reason, ‘society’s expectation has been that law enforcement agents and others would not— and indeed, in the main, simply could not—secretly monitor and catalogue every single movement of an individual’s car for a very long period.’


“Allowing government access to cell-site records contravenes that expectation. Although such records are generated for commercial purposes, that distinction does not negate Carpenter’s anticipation of privacy in his physical location. Mapping a cell phone’s location over the course of 127 days provides an all-encompassing record of the holder’s whereabouts. As with GPS information, the time-stamped data provides an intimate window into a person’s life, revealing not only his particular movements, but through them his ‘familial, political, professional, religious, and sexual associations.’ These location records’ hold for many Americans the ‘privacies of life.’ And like GPS monitoring, cell phone tracking is remarkably easy, cheap, and efficient compared to traditional investigative tools. With just the click of a button, the Government can access each carrier’s deep repository of historical location information at practically no expense.


“In fact, historical cell-site records present even greater privacy concerns than the GPS monitoring of a vehicle we considered in Jones. Unlike the bugged container [in] the Jones [car], a cell phone—almost a ‘feature of human anatomy—tracks nearly exactly the movements of its owner. While individuals regularly leave their vehicles, they compulsively carry cell phones with them all the time. A cell phone faithfully follows its owner beyond public thoroughfares and into private residences, doctor’s offices, political headquarters, and other potentially revealing locales. Accordingly, when the Government tracks the location of a cell phone, it achieves near perfect surveillance, as if it had attached an ankle monitor to the phone’s user. 


“Moreover, the retrospective quality of the data here gives police access to a category of information otherwise unknowable. In the past, attempts to reconstruct a person’s movements were limited by a dearth of records and the frailties of recollection. With access to CSLI, the Government can now travel back in time to retrace a person’s whereabouts, subject only to the retention polices of the wireless carriers, which currently maintain records for up to five years. Critically, because location information is continually logged for all of the 400 million devices in the United States—not just those belonging to persons who might happen to come under investigation— this newfound tracking capacity runs against everyone. Unlike with the GPS device in Jones, police need not even know in advance whether they want to follow a particular individual, or when. 


“Whoever the suspect turns out to be, he has effectively been tailed every moment of every day for five years, and the police may—in the Government’s view—call upon the results of that surveillance without regard to the constraints of the Fourth Amendment. Only the few without cell phones could escape this tireless and absolute surveillance.”


These constitutional concerns are precisely the reason why the search used to access Kohberger’s CLSI will be a hotly contested issue before the evidence can be used at trial. The issue of whether there was sufficient probable cause to access the CLSI will then be followed by challenges to the accuracy and verification of the evidence.


From a criminal defense attorney’s perspective, cases like Kohberger’s have the potential to either change or undermine clearly established Constitutional protections. 


It has been said that “bad facts make bad law,” and this is a horrible case that tugs at the heart strings for justice for these four beautiful young people and their families.