Justice France Charbonneau, shown in a frame-grab from video, presides over the Charbonneau inquiry looking into corruption in the Quebec construction industry Tuesday, January 22, 2013 in Montreal.THE CANADIAN PRESS/Ryan Remiorz

MONTREAL - Concerns about the credibility of Quebec's corruption inquiry are prompting new and uncomfortable questions about the resignation of Montreal's mayor last fall.

The Quebec government now says it didn't push the mayor out the door.

This after a major witness at the inquiry — whose testimony led to Gerald Tremblay's resignation — says he made up an anecdote he shared on the witness stand.

The revelation of some falsehoods in the testimony of former city employee Martin Dumont has cast new light on his claims about Tremblay.

Last fall, following Dumont's testimony, members of the government said the mayor should reflect on his political future — and Tremblay resigned soon after.

Quebec Premier Pauline Marois was asked at a news conference today whether she regretted dumping Tremblay. She denied forcing the mayor to quit and called the question "harsh."

"We did not dump Mr. Tremblay,'' Marois replied. ''We asked Mr. Tremblay ... to reflect. If he had made another decision I would have respected his decision.

"Mr. Tremblay made his decision. We did not force Mr. Tremblay to make his decision."

She also reiterated her confidence in the inquiry. However, the premier urged it to exercise caution because the "collateral damage" to people's reputation could be great.

The inquiry has heard multiple anecdotes about the former mayor's party having been corrupt, with witnesses describing how construction companies used illegal donations as a kickback in exchange for receiving public contracts.

Such payoffs were part of a broader scheme in which the value of contracts was allegedly inflated — and the extra cash was split between the Union Montreal party, corrupt bureaucrats, construction bosses and the Mafia.

Dumont shared several stories about such illegal transactions at city hall. At one point, he said, the mayor heard about illegal financing within his party and did nothing about it.

The allegation was politically devastating to Tremblay, who had always maintained his ignorance of such schemes.

Dumont has not recanted the part of his testimony about Tremblay.

But his self-described lie has created turmoil for the inquiry.

Much of Tuesday's hearing was spent dealing with his supposed lie about a receptionist for the party being forced to count $850,000 in presumably illegal cash donations.

Dumont was later caught on video admitting that he falsely implicated a young woman in the anecdote. Now he's challenging that detail, too. His lawyer is arguing that the videotaped confession is inadmissible and is accusing inquiry lawyers of obtaining the confession through trickery and by violating his legal rights.

The two days spent discussing the Dumont allegations have cut into precious time, as the commission has its October 2013 deadline fast approaching. The committee has yet to hear from numerous witnesses and has nine months to wrap up its hearings and produce a report.

The inquiry resumed Monday after a seven-week delay, which was used to hire additional staff and interview further witnesses.

News from © The Canadian Press, 2013