The RCMP have concluded their investigation into allegations of bribery in the so-called Cadman affair, saying there is no evidence to file charges.

Liberal justice critic Domenic LeBlanc had asked the RCMP to investigate allegations that the Conservatives had offered late Independent MP Chuck Cadman a $1 million insurance policy. The alleged offer was for his support on a crucial budget vote that threatened to topple the Liberal minority government in May 2005.

"We have said from the beginning that nothing improper happened here," said Conservative MP James Moore, who has handled many of the questions about the Cadman affair in the House of Commons.

"The RCMP have confirmed what we have been saying. The RCMP have found no evidence, no evidence, of any wrongdoing by the prime minister or by the Conservative party.

"The Liberals made fabricated accusations. Very soon, Liberals will see how big of a legal problem they have created for themselves," Moore told reporters.

Stemmed from biography

Moore was referring to a $2.5 million libel lawsuit launched by Harper against the Liberal party, alleging they have defamed him with statements made about the affair.

The RCMP investigation stemmed from a biography of Cadman, in which Dona Cadman, Chuck Cadman's wife, claims her husband told her that two Conservative agents met with him two days before the vote and offered him the life insurance policy in exchange for his support.

Cadman's daughter Jodi said her father told her the same story.

Cadman was dying of skin cancer when the crucial vote came up in the House. He sided with the Liberals, propping up the government and ensuring there was no summer election.

Shortly after Cadman's death in 2005, Conservative leader Stephen Harper was asked by the author of the book about the alleged insurance policy offer. Harper responded: "I don't know the details. I know that there were discussions."

Harper later explained that the offer to Cadman was "only to replace financial considerations he might lose due to an election." The conversation was recorded on audio tape.

The Tories have denied all allegations of wrongdoing. They acknowledge that two of Stephen Harper's close confidants met with Cadman, but say they only offered a repayable loan for his local riding association to cover campaign expenses if he rejoined the Tories.

Main witness deceased

LeBlanc said he wasn't surprised the RCMP concluded there wasn't enough evidence to lay criminal charges.

"A case like this, from the outset, is complicated," he told CBC News, pointing to the fact that the main witness for the case is deceased.

"We still think the prime minister has an obligation to explain to Canadians what he meant on the tape recording when he talked about financial considerations and an offer to Chuck," he said.

"Just because there's not enough evidence to lay a criminal charge, doesn't mean this isn't a sordid episode," LeBlanc said.

Harper has also launched a $2.5 million lawsuit against the Liberal party, alleging they have defamed him with statements made about the affair.

With files from the Canadian Press