How stingray devices are used by ICE

Last week, the Spanish-language Univision network published an investigative report called ICE in New York has a spy tool to hunt undocumented immigrants via their cell phones. The subject was a criminal case involving Valente Palacios Tellez, a 33 year-old Mexican native who first left his home town in 2003.

Valente Palacios Tellez currently resides in MDC Brooklyn, an administrative security metropolitan detention center operated by the Federal Bureau of Prisons.

After leaving his home town at the age of 17, Palacios Tellez was caught trying to cross the U.S border four times. His fifth attempt succeeded, and he began to work construction jobs in New York City. In the predawn hours of November 10, 2012, he got into a drunk fight outside a restaurant in Brooklyn, where a New York Police Department (NYPD) officer saw him pull out a boxcutter and attack another man. He was convicted of a felony, sentenced to two years in NY state prison, and was deported in the summer of 2014.

Somehow he managed to make his way back to Brooklyn, and whenever he crossed the U.S. border he committed his second felony offense, because entering the U.S. after being deported is a felony. On February 3, 2019, Valente Palacios Tellez was involved in another drunken brawl and was arrested by the NYPD. Charges were later dropped and the case was dismissed.

As a result of the February 2019 arrest, U.S. Immigration and Customs Enforcement (ICE) became aware that Palacios Tellez had returned to the country. On March 19, a grand jury in Brooklyn secretly indicted him for illegal re-entry to the United States. On May 16, the U.S. District Court for the Eastern District of New York approved a warrant authorizing ICE Deportations Officer Christian F. Sabatino to use devices called cell-site simulators to determine the exact location of Palacios Tellez's cell phone.

On June 5, Valente Palacios Tellez was seized by ICE agents at the home of his girlfriend, where he was living, and taken into custody by the U.S. Marshals Service.

How cell-site simulators locate a cell phone

Cell-site simulators enable law enforcement agents to snoop on criminal investigation subjects by imitating legitimate cell tower transmissions. Nearby phones are thus tricked into giving away important data such as their unique identifiers, called IMSI (International Mobile Subscriber Identity), and the user's location. These devices are generically called “stingrays”, after the StingRay family of devices manufactured by L3Harris Technologies.

Basic cell-site simulator

Stingray devices perform three different types of “man in the middle” attacks, which are:

  1. Communication interception
  2. Denial of service and service downgrading
  3. Location tracking

A cell phone can be “geolocated” using a method called trilateration. An imaginary circle is drawn around each of at least three neighboring cell towers, and the point where the circles intersect is where the mobile phone is located. In an urban area, figuring the distance between each tower and the point of intersection is a challenge, and those distances are needed to calculate the spot where the circles meet. Cell-site simulators solve this problem by tricking the phone into telling them the strength of the signal received from each one of those three cell towers. The received signal strengths are used to estimate the physical distances between each cell tower and the cellular device the investigators are trying to locate.

Now you know what trilateration is and how it is used in geolocation. From this lesson, you are expected to have gained a certain amount of respect and fear for the cellphone that you love so much.


Some of the latest cellphones and networks can report the device's exact GPS coordinates. The cell-site simulator only has to request that information and the job is done.

Department of Homeland Security policy regarding stingray devices

ICE is a child agency of the U.S. Department of Homeland Security (DHS). In October 2015, DHS Deputy Secretary Alejandro N. Mayorkas issued policy directive 047-02, Regarding the Use of Cell-Site Simulator Technology. The directive binds DHS personnel to use stingrays in a manner consistent with the Fourth Amendment to the U.S. Constitution, as well as legal code enacted as part of the Electronic Communications Privacy Act of 1986, referred to as the Pen Register Statute.

The Fourth Amendment protects citizens against unreasonable searches and seizures by the government. When applied to immigration law enforcement, it limits the issuance of search warrants to cases where ICE has probable cause to believe that the person they are seeking is removable from the United States. ICE cannot use stingray devices without first obtaining a search warrant.

A pen register is an electronic device that records all numbers called from a particular telephone line or mobile phone. Recall that cell-site simulators obtain the IMSI number uniquely identifying the phone. The Pen Register Statute declares that no person may install or use a pen register without first obtaining a court order. DHS directive 047-02 mandates ICE agents to either include in their applications for search warrants information included in applications for court orders under the Pen Register Statute, or to seek a warrant and a pen register court order concurrently.

How stingray devices are used by ICE

Organizationally, ICE is composed of four directorates. The two operational directorates of interest here are Enforcement and Removal Operations and Homeland Security Investigations. Enforcement and Removal Operations (ERO) is concerned with the actual removal of illegal aliens, while Homeland Security Investigations (HSI) conducts criminal investigations.

In May 2017, Senator Ron Wyden (D-OR) sent a letter to then-acting ICE Director Thomas Homan, requesting information on how cell-site simulators are used by ICE. In his response, Thomas Homan explained that ICE operates cell-site simulators under the DHS 2015 directive requiring the obtaining of search warrants, and that they are used in support of criminal investigations requiring judicial process, and not for administrative violations under the Immigration and Nationality Act. That means that stingrays are used by HSI during criminal investigations, but are not used by ERO for civil immigration law enforcement.

More simply put, an illegal alien needs to have done something really, really bad before ICE would search for him using a stingray device.