Nigel Wright's $90,000 payment to cover Senator Mike Duffy's expenses was offered only with certain conditions, according to court documents that also show several people in the Prime Minister's Office knew about the offer.

New details about the payment and the circumstances around it are contained in an application to the court by the RCMP seeking documents from the Senate and other material for its investigation of Duffy's expense claims.

RCMP investigator Cpl. Greg Horton wrote he has reasonable grounds to believe Duffy committed breach of trust and fraud on the government because of inappropriate expense claims and because he accepted the money from Wright.

Wright was Prime Minister Stephen Harper's chief of staff who resigned over the matter once it was reported in the media in May.

The RCMP met with Wright's two lawyers on June 19, and they revealed that while there was no written contract between Wright and Duffy, Wright asked for two conditions to be met in return for the $90,000: that Duffy stop talking to the media and that he reimburse the government immediately with the money.

The lawyers, Patrick McCann and Peter Mantas, said Wright was not directed by anyone to make the offer, that he believed it was the ethical thing to do so that taxpayers weren't on the hook, and that he and Duffy were not friends.

But the decision came only after the Conservative Party of Canada considered paying the bill for Duffy's inappropriately claimed expenses when it was thought he owed $32,000. The party has a fund controlled by Duffy's colleague in the upper chamber, Senator Irving Gerstein.

When the amount owed jumped to $90,000, the party decided it was too much to cover. Duffy was concerned he didn't have the money to cover the reimbursement, the lawyers told the RCMP, and he was also worried that if he didn't claim a primary residence in Prince Edward Island, his eligibility for a Senate seat would be at risk.

Some PMO staff knew

Senators Patrick Brazeau and Mac Harb have been asked to pay taxpayers back for housing and travel allowance claims. Harb paid $51,000 back on Friday.

Wright didn't offer to cover their expenses, the lawyers said. He got a bank draft from CIBC on March 25 that went to Duffy's lawyer, then Duffy wrote a personal cheque to pay the government.

Harper says he didn't know about Wright giving the money to Duffy until it was revealed in the media and in question period on May 28. The prime minister said Wright made the decision on his own and kept the matter to himself until May 15.

But the court documents say Wright let the RCMP know on June 21 that he told Gerstein and three people in Harper's office that he was going to write Duffy a cheque: David van Hemmen, Chris Woodcock, and Benjamin Perrin.

Perrin worked in the Prime Minister's Office as Harper's legal adviser and some media reports have said he was involved in arranging the Duffy deal, a claim he denies. Perrin issued a statement on May 21 saying he "was not consulted on, and did not participate in" Wright's decision and that he never talked to Harper about the matter. He recently left his job in the PMO and is employed by the University of British Columbia.

Conditions attached

Van Hemmen worked as Wright's assistant and Woodcock is director of issues management in the PMO.

The RCMP investigator says in the court document that he believes the conditions attached to the payment offer back up the idea that there was an agreement between Wright and Duffy involving the $90,000 and the Senate report that ended up not being critical of the Prince Edward Island senator.

It has been reported in the media that Duffy agreed to say publicly he made a mistake and was paying the money back in exchange for Wright actually paying the money and a Senate report that would go easy on him.

This would amount to fraud on Duffy's part, according to the RCMP, and his per diems and his housing allowance that he should not have claimed would be breach of trust.

The documents lay out details of how the Senate report on Duffy's expenses was amended by Conservative senators David Tkachuk and Carolyn Stewart-Olsen. Stewart-Olsen was interviewed by the RCMP and said the report removed the critical portions about Duffy because he had paid the money back, she didn't know Wright actually paid the money, and that no one told her and Tkachuk to change the report from its draft versions.

Duffy was reached by CBC News on Friday and said he had no comment. Wright's lawyer said he is co-operating with the RCMP and has no further comment.

Harper's spokesman, Andrew MacDougall, was asked by CBC News to respond to a long list of questions Friday including what role, if any, van Hemmen, Woodcock, Perrin played and whether Harper knew his party was willing to pay for Duffy.

"This file was handled by Nigel Wright and he has taken sole responsibility for his decision to provide his personal funds to Duffy," MacDougall responded, adding that the court document states Harper was not aware of the offer and found out about it on May 15.

CBC News also asked Conservative party president John Walsh a series of questions. Party spokesman Fred DeLorey responded instead by saying only that the Conservative Fund did not pay for Duffy's expenses.

NDP MP Alexandre Boulerice said the details revealed by the court document are "troubling." He said in an interview that Harper's version of events "is just not true."

"It's not a personal issue between Mr. Wright and Mr. Duffy because there was a first attempt to cover up this scandal by the Conservative Party," he said.

Boulerice said he wants to know if Harper knew the party was going to pay for Duffy and whether he asked his staff who was involved once the news about Wright's payment broke.

"There's a lot of questions to answer now and Mr. Harper should do the right thing and tell the truth," he said.

Heritage Minister James Moore said Friday that anyone who abuses the system should be held accountable and should "leave public office with their head hung in shame."

"I think when you see people like Senator Duffy or others taking taxpayers' money, using it in an arrogant, irresponsible and perhaps illegal way, I think taxpayers are rightfully upset, rightfully mad and they should be," he told reporters at an event.

Liberal Leader Justin Trudeau said it's curious that the Conservative party would be willing to pay for Duffy to "make his problems go away" and that Harper has not been transparent with Canadians.

"It's been a real disappointment and it's frustrating, quite frankly, to have to be learning about what happened in the Prime Minister's Office through a very serious police investigation, and this Prime Minister has completely lost any credibility with the Canadian people because of his mishandling of this scandal," Trudeau told reporters.