Canada's privacy commissioner has found six cases of the RCMP's use of cell phone tracking devices illegal. Mobile device identifiers sometimes called IMSI catchers interact with a nearby phone and read its International Mobile Subscriber Identity, or IMSI in much the same manner as a cell phone tower would do. With information thus obtained, it is possible to track the phone, and even intercept text messages or calls.
The Privacy Commissioner on complaint of OpenMedia (a group advocating for surveillance-free internet) undertook an investigation and found that between 2011 and 2016, the RCMP used IMSI catchers in 125 criminal investigations, including cases related to national security, organized crime and during kidnappings. The RCMP did first obtain a warrant to intercept but for a brief period between March and June 2015, the RCMP conducted warrantless searches. The Privacy Commissioner has deemed these intrusions illegal.
The Correctional Service of Canada at its Warkworth Institution also used such a device that resulted in the capture of private communications of guards and people outside prison fences. That intrusion has also been investigated by the OPP. In its report recently completed, the OPP also concluded that the breaches were illegal but the force concluded there was insufficient likelihood of criminal conviction and closed its file.