OTTAWA — Investigators looking into corruption within Montreal’s police force for almost six months focused their attention on one of Quebec’s most prominent journalists even though he had neither reported on the corruption case nor had any strong connection to it.

Advocates of press freedom expressed alarm about revelations this week that the police had captured calls and text messages to and from an iPhone belonging to the journalist, Patrick Lagacé, a columnist with the Montreal newspaper La Presse, and were given permission to track his movements by using the phone’s GPS function.

In response, legal scholars have questioned the legality of the police action, and journalism organizations and politicians have condemned the police monitoring. On Tuesday, the government promised greater protections for journalists.

On Monday, La Presse reported that Mr. Lagacé had been spied on as part of an effort by Montreal’s police force to find the source of leaks to news outlets about an internal inquiry into allegations that members of a drugs and street-gang unit had fabricated evidence.