The former head of a government anti-collusion unit, Jacques Duchesneau, testified the previous day that provincial political parties are flush with "dirty money" — with up to 70 per cent of their cash raised illegally.
That spurred reactions from various political actors in the province, from the premier to his opponents to the chief electoral officer.
It also prompted pointed questions on the witness stand as Duchesneau and his ex-colleagues faced an intense cross-examination by lawyers representing various interested groups. One party's lawyer all but described him as a rogue operator.
The exchanges grew so fierce at one point that the presiding judge, France Charbonneau, cautioned lawyers that she would "not allow the cross-examination to be this aggressive."
Among the concerns raised by lawyers was Duchesneau's decision to independently investigate claims of illegal political financing.
He was relieved of his duties at the unit after he leaked a secret report that spoke of Mob ties to the construction inquiry, and kickback schemes that benefited politicians.
But he has kept digging.
Duchesneau, a one-time Montreal police chief, said that in the last four months he had produced around 50 pages of notes based on interviews he conducted with anonymous sources.
A lawyer for the Opposition Parti Quebecois — which has been accusing the governing Liberals of corruption for months — accused Duchesneau of taking the law into his own hands.
"I am of the opinion that Mr. Duchesneau's voluntary report hurts his responsibility as the head of a public organization," said the PQ's lawyer, Estelle Tremblay.
"Mr. Duchesneau, without any authorization, improvised as an investigator, compiled files on others, and in doing so compromised his impartiality as a representative of the state when he was leading the (anti-collusion unit)."
Duchesneau has given his notes to the inquiry's investigators.
Charbonneau has turned down a request by Tremblay and other lawyers to have the follow-up report included with the other public documents tabled at the inquiry.
Duchesneau, for his part, denied having compiled files on specific individuals. He said he simply met with people who contacted him after he left the anti-collusion unit.
"I met people who had things to tell me," he said in response to Tremblay's questions. "I took notes and I consigned them to the report."
Lawyers have expressed skepticism at some of Duchesneau's claims. He and his former colleagues have given several vague answers during their five days of testimony.
They have repeatedly been pressed to explain how they arrived at their conclusions.
But on the issue, for instance, of who their sources were they have avoided specifics. They explained that their sources either feared retribution, or have been threatened. Duchesneau has described a "culture of intimidation" within Quebec's Transport Department, which he said makes sources difficult to find.
But lawyers for the Quebec government questioned whether the anti-collusion unit might have been making grandiose claims based on little evidence.
Martin Morin, who worked alongside Duchesneau in the anti-collusion unit, admitted he had made some assumptions when arriving at certain numbers cited in the report.
That brought a sharp reply from government lawyer Benoit Boucher: "How many assumptions did you make in this report?" Charbonneau issued her warning not long after Boucher completed his line of questioning.
As Duchesneau and his colleagues sought to defend their allegations, much of Quebec's political class was still digesting Tuesday's testimony.
The province's elections watchdog said he was "surprised" by Duchesneau's 70 per cent figure.
Quebec's two main political leaders sought to distance their parties from the claims of widespread illegal financing.
Quebec Premier Jean Charest, who is rumoured to be considering an election call later this summer, stressed that whatever the validity of Duchesneau's remarks, his own party was clean.
"Me, I'm sure of one thing: the Liberal Party of Quebec does its financing correctly, according to the rules," he told reporters while attending a United Nations conference in Brazil.
"We respect the laws."
Parti Quebecois Leader Pauline Marois had even harsher words for Duchesneau — stating outright that she didn't believe him.
"I can state, without reserve, that the Parti Quebecois doesn't use this kind of financing," she told a local radio station Wednesday morning.
"I don't know where he got that. He has to offer proof for these allegations."
In 2010, the provincial elections watchdog forced both the Liberals and the PQ to return tens of thousands of dollars in illegal donations made by an engineering firm.
But there was at least one politician who did lend some support to Duchesneau.
Quebec City Mayor Regis Labeaume said he agreed with the suggestion that influence-peddling was rampant in certain municipalities, to the point that elections can be fixed.
"For sure that exists somewhere, there's no doubt about it," he said in Quebec City.
Duchesneau's cross examination is expected to continue Thursday.