Senator Mike Duffy said Thursday he wants a "full and open inquiry" to answer the many questions Canadians have about the spending scandal that prompted him to leave the Conservative caucus and now has the RCMP asking the Senate for more details about spending rules.

Duffy said he has not been contacted by the RCMP and that he will co-operate with anyone who is doing an investigation into his travel and housing allowance claims.

"I think Canadians have a right to know all the facts and I'm quite prepared in the appropriate place and time to give them the whole story," Duffy told reporters as he left the Senate and walked to his car. "There are bits and pieces out there, it should all be put together in one place and there will be some place to do that."

Duffy had not spoken in public or accepted interview requests since it was revealed last week that Prime Minister Stephen Harper's chief of staff Nigel Wright had written a cheque for more than $90,000 so Duffy could pay back housing allowance expenses that he says he may have claimed in error.

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An external audit by Deloitte was done on Duffy and senators Mac Harb and Patrick Brazeau to examine where their primary residence is and if they had properly claimed an allowance for a second residence in Ottawa. Duffy repaid the money before the audit was finished and did not co-operate with the process.

Harper says he learned about the cheque payment through the media — a claim the opposition parties are casting suspicion on — and that he wouldn't have approved if he had known about it. Wright resigned on Sunday because of the secret cheque. His departure came days after news of the cheque first broke on Tuesday night and after Harper's office initially said Wright still had the prime minister's confidence.

At a Thursday press conference in Colombia, where he is on a South American trade mission, Harper was asked why he stood by Wright for days if what he did wasn't acceptable.

"He should have told me earlier, that's why I accepted his resignation. Upon reflection, should I have reached that conclusion earlier? Perhaps. But I think that is the correct conclusion," Harper said.

Harper was asked about the terms of the deal between Wright and and Duffy, and if lawyers were involved. He said he's not aware of any formal agreement and that Wright will have to answer to Parliament's ethics commissioner for his actions.

Harper said the expenses charged by Duffy, Harb and Brazeau were "inappropriate," that his government has taken "the appropriate actions" and will "hold people accountable."

'No idea' if Harper knew about cheque

Duffy, who resigned from the Conservative caucus last Thursday but hopes to rejoin it in the future, was asked if Harper knew about his deal with Wright. "I have no idea. I would find … I just don't know," he responded. He was also asked to explain a media report claiming he said he had gotten a Royal Bank loan to pay the money back, contradicting what is known about the Wright cheque.

"Just wait for it all to come out," he said.

The Senate voted earlier this week to send the report on Duffy's expenses back to the internal economy committee that is currently being accused by the Liberals and NDP of whitewashing the version that was released on May 9. The Liberals are pushing for the normally in-camera meetings to be held in public and Duffy said he supports that.

"Of course, it has to be done in public, there's no question," he said. The Prince Edward Island senator said that whether it is a Senate committee or another Deloitte audit, he welcomes the scrutiny.

"Canadians deserve answers, I want to give them answers, and eventually, hopefully not too long, they will get the answers," he said. "We need a full and open inquiry so that it all gets aired."

Duffy declined to questions from reporters about the different versions of the Senate report, his relationship with Wright, and about his lawyer.

He flatly rejected a question about whether he plans to resign or stay in the Senate "Pfffft. Of course, I'm a senator, why wouldn't I?"

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Duffy is now sitting as an Independent senator along with Pamela Wallin, who resigned from the Tory caucus on Friday while her travel expenses remain the subject of an external audit.

Harb and Brazeau are also both sitting as Independents and disputing the orders to pay money back for the housing allowances they claimed. Harb left the Liberal caucus when the audit was released and Brazeau was kicked out of the Conservative caucus because of a criminal charge he is facing in an unrelated matter.

RCMP asks Senate for rules dating back a decade

The opposition parties spent much of Thursday pushing the government to explain who was behind the decision to edit the original Senate committee report on Duffy's expenses, and why.

But the opposition parties aren't the only ones seeking more information. The Senate confirmed Thursday that the RCMP is continuing its probe of the Deloitte audits that were done on Duffy, Harb and Brazeau.

A letter from the RMCP dated May 16 and tabled in the Senate says the force wanted copies of Senate policies "in order to make a determination as to whether there are grounds to commence a criminal investigation."

Supt. Biage Carrese, of the sensitive and international investigations unit of the RCMP's national division in Ottawa, wrote that the RCMP is "conducting a review" of the Deloitte audits. He requested copies of guidelines over the last 10 years related to travel and living expenses and other administrative rules. The RCMP also wanted the Senate calendars for the last decade to determine when the upper chamber was sitting.

Senate Speaker Noël Kinsella informed the Senate of the request and said the information had been passed on to the RCMP. The police force does not confirm whether it is conducting criminal investigations into matters.

The government was asked in question period if Harper's office had been approached by the RCMP and Heritage Minister James Moore responded that it had not.

"The Senate committee's report on Senator Duffy was whitewashed. Who ordered the members of the committee to whitewash the Duffy report and why did a majority of the senators on the committee agree to co-operate in this coverup?" Liberal MP Judy Foote said at a news conference with other Liberals earlier in the day.

Much of the focus was on the two Conservative senators who handled the draft report on Duffy's expenses, Carolyn Stewart Olsen and David Tkachuk. Liberal Senator George Furey was the third senator on the steering committee that wrote the report before it was presented to the Senate's internal economy committee.

Conservatives deny they were ordered to edit

Tkachuk is not on Parliament Hill this week because of recent surgery, but he gave some media interviews and said he was not ordered by anyone to write the report a certain way. He did say that he had a "number of discussions" with Wright about Duffy, and sought advice for his report from the PMO, fellow senators, members of the media, and others.

Stewart Olsen told CBC News that as chair of the internal economy committee it makes sense for Tkachuk to be in touch with people in the PMO and that she also had discussions during the course of the report.

"I have spoken with some people in PMO. I don't speak to them a lot," she said. "No. The report is as we produced it, we changed it ourselves as we edited," she responded when asked if she was told to change the report.

The final report on Duffy released by the committee on May 9 along with the reports on Harb and Brazeau lacked key paragraphs that had been in the first version related to findings about Duffy's primary residence and his co-operation with the audit.

The Duffy report also used different language from that used in the reports on Harb and Brazeau. There is no mention of the rules on housing claims being clear in his report, for example, as there is in the other two.

Olsen said the reports were written by different groups and "were never meant to be in lockstep."

Prime Minister Stephen Harper speaks with Conservative Senate Leader Marjory LeBreton on Tuesday during a caucus meeting. Fred Chartrand/Canadian Press. (Fred Chartrand/Canadian Press)

Opposition MPs are raising questions about whether Conservatives were influenced by the Prime Minister's Office to go easy on Duffy, and if so, whether that was done in exchange for Duffy's repayment of $90,172.

"We are not aware of any legal agreement between Mr. Wright and Mr. Duffy. It is as simple as that," Moore said in question period when asked who in the PMO knew about Wright's repayment. Harper is on a trip to Colombia.

A Liberal on the Senate internal economy committee tells CBC News that the draft report was altered in the final 24 hours before it was tabled in the Senate on the afternoon of May 9.

The Harb and Brazeau reports, prepared by a subcommittee struck in the fall to examine senators' housing allowances, were considered and approved by the internal economy committee on May 8. The committee's meetings are held in-camera behind closed doors.

When the committee reconvened on May 9, Olsen introduced a motion to change the Duffy report, including deleting the draft report's references to the residency rules being "very clear" and "unambiguous." Another change initiated by Olsen deleted the draft report's statement that Duffy's travel patterns were not consistent with maintaining a primary residence on P.E.I.

Duffy and his lawyer were in the room at the time.

In a move sources suggest is unprecedented for the internal economy committee, which usually makes its decisions on a consensus basis, a vote was taken on whether to change the report. Committee members split along party lines and Tory votes carried the day.

Later that afternoon, a relatively raucous scene emerged in the Senate as the reports were tabled, with some senators objecting to being asked to consent to reports they hadn't seen.

Furey made it clear when he spoke in the Senate that while it represented the majority on the committee, the report was not unanimous.

The committee of internal economy deals with senators' expenses. The subcommittee was struck when questions were raised about Brazeau and whether he was properly claiming a housing allowance that senators are entitled to worth up to $22,000 per year. The money is for a secondary residence in Ottawa if their primary residence is more than 100 kilometres away.

The questions about Brazeau prompted a widespread review of senators' travel and housing claims, and led to the three audits plus the one on Wallin.

A copy of the original Duffy report was obtained by CBC News. It showed that the committee concluded Duffy's primary residence is in Ottawa. It said his declaration that his cottage in P.E.I was his primary residence was not supported based on his travel patterns and time spent in Ottawa. This finding, however, was not included in the final report that was released May 9.

Duffy, a former journalist in Ottawa, has had a home for years in the capital.

Key paragraphs removed

Other key paragraphs were removed from the first version of the report and opposition parties want to know why.

"This is a scam being perpetrated on the Canadian people and the Senate has no credibility," the NDP's ethics critic Charlie Angus said.

The Senate voted on Tuesday to send the Duffy report back to the internal economy committee for a second look.

Angus pointed to the close connection between Harper and Olsen and noted that she sat on the steering committee that was driving the writing of the Duffy report. "This keeps going back to the prime minister," he said.

Olsen has a long history with Prime Minister Stephen Harper that dates back to his time in the Canadian Alliance Party. She is one of his most loyal advisers, and worked as his press secretary and later as his chief communications strategist. Harper appointed her to the Senate in 2009.

Marjory LeBreton, the government's leader in the Senate, was asked about the alleged whitewashing of the report Thursday during the Senate's question period and about Tkachuk's comments. She said she would review them and report back.

LeBreton also fielded complaints from Liberal senators about the same committee that handled the Duffy report being tasked with looking at it again. She said she has faith in the committee and that it's up to its members to accept or reject Cowan's request for the meeting to be in public.