According to a new report from the Wall Street Journal, the Justice Department has been operating a surveillance program that uses fake cell phone towers placed on airplanes to collect identifying data from a vast number of cell phones.

In this program, Cessna aircraft operated by the US Marshals Service fly over most of the United States, embedded with small devices called “dirtboxes” by insider sources familiar with the program. The dirtboxes mimic cell phone towers which prompt cell phones to reveal their identifying information and location, including phones with encryption technology. The program has been utilized by the Justice Department and US Marshals Service since 2007.

In September, Benswann.com reported that fake cell phone towers, or “interceptors,” had been discovered near military bases throughout the United States.

The program insiders have said that this program is in place for the purpose of “locating cellphones linked to individuals under investigation by the government, including fugitives and drug dealers, but it collects information on cellphones belonging to people who aren’t criminal suspects.” The individuals providing information about the program said that data from tens of thousands of phones can be collected after one flight.

The sources claimed that the dirtboxes are able to determine which phones belong to suspects, but did not disclose whether or not the data belonging to unsuspected individuals is stored.

These devices bypass requests for location and identifying data from phone companies such as Verizon and AT&T by gathering the information themselves. A spokesman for Verizon said the company was unaware of such an operation, while AT&T and Sprint declined to comment.