Whistleblower Ken Pereira is among those welcoming the news of a public inquiry into how police were tracking journalists in Quebec.

Pereira was a union organizer who learned how the mafia was controlling the Quebec Federation of Labour, and how his former boss, Jocelyn Dupuis, had stolen at least $63,000 from the union.

He was offered luxury cars, cash, and strippers to stay quiet -- but instead he went public, but even then, discovered police had an intense interest in knowing which reporters he talked to.

"A lot of them wanted to know what Radio Canada, TVA, what CTV was working on when they came to see me. So what does than mean, it means they were trying to get some information that they couldn't get from their own lines," said Pereira.

He believes if police are spying on journalists, whistleblowers like him will hesitate even more before going public.

"If an entity like the cops, the authorities, the policeman is in this little, between you and me, well it might really affect us," said Pereira.

The evidence that police in Quebec are monitoring conversations involving investigative journalists is growing.

Alain Gravel of Radio Canada believes the Sureté du Quebce was spying on him from 2008 until 2013.

Eric Thibault of the Journal de Montreal said the SQ had a list of all his calls from 2009 until 2013.

The supposed reason for the monitoring was because journalists were writing about another QFL leader, Michel Arsenault, but Thibault, for one, never wrote about Arsenault until 2014.

Radio Canada executives hope a public inquiry will reveal just how many reporters were being tracked.

"We want to know how widespread this was, was this an isolated incident or was this a practice that was widespread," said Michel Cormier, the news director for Radio Canada.

Prime Minister Justin Trudeau said Thursday that he has been assured by the heads of CSIS and the RCMP that those agencies are not monitoring reporters.

But the Quebec Federation of Journalists is not convinced, pointing out that RCMP investigators tailed reporters from La Presse working on a piece about Adil Charkaoui, who was under a security certificate.

"We know the RCMP spied on reporters and we are extremely worried about that," said Jean-Thomas Leveille.

The federation is calling for stronger laws to protect whistleblowers and reporters.