This request concerns the ability of law enforcement agents to obtain records from cell phone companies that reveal the past or present travels of cell phone users.

Cell phone technology has given law enforcement agents the unprecedented ability to track individuals’ movements. As of December 2010, over 96 percent of the overall population of the United States carried a cell phone—an estimated 302.9 million people. Even the most basic cell phones can be tracked. Cell phones can be tracked in real time, and cell phone companies frequently retain records on the past travels of their customers.

The Constitution protects against unreasonable searches, and if the Massachusetts State Police obtains cell phone location records, the conditions under which it does so are of great public interest. The ACLU of Massachusetts believes that the Constitution does not permit law enforcement agents to track the location of cell phones without obtaining a warrant and demonstrating probable cause.