Geofence warrants, a type of reverse search warrant, compel companies, like Google, to turn over substantial information about devices interacting with their technology within a particular geographic region. For this reason, geofence warrants mark an unprecedented increase in the government's ability to locate individuals without investigation. This primer will show you how geofence warrants are constructed and outline strategies to challenge these warrants when they appear in criminal cases. 

Defense lawyers increasingly are dealing with cellphones and location issues. Per Call Measurement Data files provide an estimate of the location of a cellphone. (Call Detail Record files, on the other hand, provide the location of the cell tower that served a call.) Richard Miletic explains the technology used, the error rate, and the basis to exclude PCMD under Daubert.

A cell phone’s location can be detected through cell site location information (CSLI) or global positioning system (GPS) data. CSLI refers to the information collected as a cell phone identifies its location to nearby cell towers.

In recent years, the government has increasingly turned to hacking as an investigative technique. Specifically, the Federal Bureau of Investigation (“FBI”) has begun deploying malware: software designed to infiltrate and control, disable, or surveil a computer’s use and activity.

Coalition letter to the House Judiciary Committee regarding the need for reforms to the drafted USA FREEDOM Reauthorization Act of 2020 relating to mass and unwarranted surveillance.

Digital Forensics Guide Cell Phone Location and Tracking Forensics. 

6th Annual Post-Conviction Conference

The outline of the PowerPoint presentation on cell phone tracking and cell site analysis by JR Computer Consulting. 

A PowerPoint presentation on cell phone tracking and cell site analysis by JR Computer Consulting. 

A detailed paper on the nature of cell phone tracking cases and how to navigate a case involving cell phones, their tracking, and records.

Brief of Amici Curiae Electronic Frontier Foundation, Brennan Center for Justice, The Constitution Project, National Association of Criminal Defense Lawyers and National Association of Federal Defenders in Support of Petitioner.

Argument: There has been a dramatic increase in location data generated by cell phones, collected by third parties, and routinely obtained by law enforcement without a warrant. Cell Site Location Information (CSLI) paints a revealing portrait of a person's movements, presenting even greater privacy concerns than the GPS tracker at issue in Jones. The Third-Party Doctrine is "ill-suited to the digital age" and should not apply to CSLI. 

En Banc Amici Curiae Brief of the National Association of Criminal Defense Lawyers in Support of Appellant Quartavious Davis.

Argument: For good reason, the Supreme Court has nearly always rejected the claim that the Fourth Amendment does not regulate advancement in surveillance technology, including location tracking. Obtaining the location data sent by the defendant’s telephone without a warrant supported by probable cause was an unconstitutional seizure of the defendant’s private information. In this case, the investigating officers could not have believed in good faith that the order requiring production of the defendant’s location tracking records was constitutional.

Brief of Amici Curiae of the American Civil Liberties Union Foundation, American Civil Liberties Union Foundation of Florida, Inc., Center for Democracy & Technology, Electronic Frontier Foundation, and National Association of Criminal Defense Lawyers.

Argument: Warrantless acquisition of long-term historical cell site location information violated defendant’s reasonable expectation of privacy under the Fourth Amendment. Defendants’ cell site location information obtained by the government reveals invasive and accurate information about their location and movements over time. Obtaining 67  days’ worth of cell phone location data is a “search” under the Fourth Amendment requiring a warrant based upon probable cause. Cell phone providers’ ability to access customers’ location data does not eliminate cell phone users’ reasonable expectation of privacy in that data. Even if the good faith exception applies, this court should decide the Fourth Amendment question.

Brief of Amici Curiae of the American Civil Liberties Union Foundation, American Civil Liberties Union Foundation of Maryland, Center for Democracy & Technology, Electronic Frontier Foundation & National Association of Criminal Defense Lawyers in support of defendants-appellants’ appeal seeking reversal.

Argument: Warrantless acquisition of long-term historical cell site location information violated defendants’ reasonable expectation of privacy under the Fourth Amendment. Defendants’ cell site location information obtained by the government reveals invasive and accurate information about their location and movements over time. Obtaining 221 or 14 days’ worth of cell phone location data is a “search” under the Fourth Amendment requiring a warrant based upon probable cause. Cell phone providers’ ability to access customers’ location data does not eliminate cell phone users’ reasonable expectation of privacy in that data. Even if the good faith exception applies, this court should decide the Fourth Amendment question.

Brief of Amici Curiae American Civil Liberties Union Foundation, American Civil Liberties Union Foundation of Michigan, Brennan Center for Justice, Center for Democracy & Technology, Electronic Frontier Foundation & National Association of Criminal Defense Lawyers in Support of Defendants-Appellants’ Seeking Reversal.

Argument: Warrantless acquisition of long-term historical cell site location information violated defendants’ reasonable expectation of privacy under the Fourth Amendment. Defendants’ cell site location information obtained by the government reveals invasive and accurate information about their location and movements over time. Obtaining 127 or 88 days’ worth of cell phone location data is a “search” under the Fourth Amendment requiring a warrant based upon probable cause. Cell phone providers’ ability to access customers’ location data does not eliminate cell phone users’ reasonable expectation of privacy in that data. Even if the good faith exception applies, this court should decide the Fourth Amendment question.