No sooner had the Conservatives unveiled a candidate meant to epitomize accountability, than leaked documents showed Allan Cutler was once investigated for a possible breach of ethics.

A former civil servant best known to Canadians as the man who first exposed the federal sponsorship scandal, Cutler's candidacy was announced at his new campaign office in Ottawa South.

"Allan Cutler is a genuine hero," Harper told supporters Monday, heaping praise on the retired bureaucrat credited with blowing the whistle on bid-rigging and political interference in the now-defunct sponsorship scheme.

But before the cheers had a chance to even die down, the shine was threatening to rub off the would-be star Tory candidate.

According to leaked documents obtained by CTV News, after his retirement, Cutler was the subject of a federal ethics probe.

After leaving a job, retired civil servants are forbidden from dealing with their former departments for one year. But Montreal-based ARI Financial claims Cutler offered to help them retain the management of the government fleet of vehicles.

According to a letter the company sent Public Works, "We were left with the impression that he could leverage the information and knowledge he has acquired as a public servant to our advantage."

When Cutler, 56, wound up working for a competing bidder, ARI demanded an investigation.

When asked about the probe, Cutler told CTV News he did nothing wrong.

"No, I never said leveraging information. I offered to help them with my experience in bidding to governments," he said, noting that a Public Works investigation concluded he had not been in a conflict of interest.

Defending his candidate, Harper accused the Liberals of mounting a smear job.

"Jean Chretien and his people tried to discredit Allan Cutler,'' Harper said.

"Now Paul Martin and his people are trying to do the same thing, discredit Allan Cutler. And why? Remember this. They really only have only one regret about the sponsorship scandal -- they regret that they got caught.''

But the allegations aren't just coming from the Liberals.

Lawyer Allan Riddell, who ran as a Conservative in Ottawa South last time Canadians were called to the polls, says the party promised to him $50,000 to step aside for Cutler.

"I stand by that," Riddell told CTV News, reiterating his claim that the cash offer was made to cover expenses incurred seeking the nomination for this year's vote.

But Harper sharply denied the suggestion.

"The party does not have an agreement to pay Mr. Riddell these expenses, and Mr. Riddell has not been paid anything to date," he said, explaining that the party's national council had decided Riddell was not an "acceptable'' candidate.

Harper did not elaborate, however, other than to say Riddell's last campaign was "troubled.''

Cutler, who now works as a teacher and consultant on government ethics, is running on the Conservative ticket in the riding of Ottawa-South. His chief political opponent for the Jan. 23 vote is Liberal David McGuinty -- the brother of Ontario Premier Dalton McGuinty.

Prepared with a report by CTV Ottawa Bureau Chief Robert Fife