Securus Technologies is a Texas-based company, specializing in providing and monitoring calls to prison inmates. Securus came into the spotlight earlier this month, when a former Missouri sheriff was found using the company's service to repeatedly track people without a warrant. The New York Times reports that between 2014 and 2017, former sheriff Cory Hutcheson used the service at least 11 times, allegedly tracking a judge and members of the State Highway Patrol.

Securus obtains tracking information through a company called LocationSmart, which in turn has agreements with most U.S. carriers. Earlier this month, Senator Ron Wyden of Oregon wrote a letter to various carriers asking them to independently verify that these requests are made lawfully.

Read More