Montreal police spied on a La Presse journalist for months to try to learn who his sources were, the newspaper reported on Monday.
The newspaper reported that police obtained at least two dozen court-approved surveillance warrants in 2016.
Those warrants allowed them to know who journalist Patrick Lagace called and texted and gave them access to his location through the phone’s GPS.
Montreal Mayor Denis Coderre called the spying “worrisome” and “unacceptable”.
The surveillance was part of an internal probe into allegations that Montreal police had fabricated evidence in gang and drug investigations.
Two officers were charged this summer as a result of the internal investigation.
Revelations that police had been monitoring Mr Lagace’s phone shocked Canadian media and free speech advocates.
La Presse deputy managing editor Eric Trottier said the surveillance was an “unequivocal attack against the institution of La Presse and against the entire journalistic profession”.
“Are you a journalist? The police spying on you specifically to ID your sources isn’t a hypothetical. This is today,” tweeted whistleblower Edward Snowden.
“One must protect the freedom of the press,” he said.
Montreal police monitored journalist Patrick Lagace’s phone