The sensational suggestion from Coalition Avenir Quebec Leader Francois Legault comes in the heated and politically unpredictable atmosphere of an election campaign.
The charge stems from a dispute involving the commission looking into the construction industry, its Mafia ties, and illegal political fundraising.
The spat began with a tantalizing question: Why would a star witness at the inquiry, now running for Legault's party, make such sweeping allegations about rampant corruption while he testified in June, but remain so stingy with specific proof?
When Jacques Duchesneau testified in June, the anti-corruption whistleblower said Quebec politics was awash in dirty money and 70 per cent of the cash raised by parties is done so illegally.
He has yet to provide any specific names or examples. Meanwhile, he's now the star election candidate for Legault's party and his entry in the race has been described by pundits as a potential game-changer.
Duchesneau says inquiry lawyers never asked him the right questions.
An inquiry lawyer snapped back Tuesday, saying Duchesneau provided vague information and the questions asked on the stand stemmed from what he had said during pre-interviews.
That lawyer, Sylvain Lussier, was also quoted in news reports questioning the quality of a private report Duchesneau submitted which has yet to be made public.
Now the leader of Duchesneau's party is questioning the inquiry's integrity.
He suggested perhaps commission counsel had something to hide, and may have been trying to protect the Charest government by skirting awkward questions in June.
"Why weren't people asking questions? Why wasn't Mr. Lussier asking questions? Was there something to hide? Was he protecting the government?" Legault said.
"It's pretty serious. We've got a Crown lawyer who says, 'I'm not happy with the answers,' but he didn't ask the questions."
Legault says his candidate is ready to return to the witness stand anytime as of next week, if the inquiry is willing to momentarily suspend its summer break.
"We'll give (Lussier) a chance. We're saying Mr. Duchesneau is available, as of Monday. Let's start the commission again for a few days. Mr. Duchesneau can testify and answer all the questions."
It was the premier who named Duchesneau to run an anti-collusion unit within the government, although he was ultimately fired after that unit was rolled into a larger body and there were run-ins with the new boss.
Duchesneau then leaked an internal report to the media — the first of two he has produced — in order to pressure the government to call an inquiry. His gambit was successful. Premier Jean Charest, who had refused to call an inquiry for two years, relented in the face of public outrage.
Now the Liberal premier is challenging Duchesneau to come forward with names.
He says it's unfair that a witness — who is now his political opponent — would have made an all-encompassing slur without backing it up with proof.
Duchesneau says he would only offer those specifics on the stand, where he has legal immunity. It's unclear whether the inquiry could be reconvened during its summer break, in the middle of an election campaign.