Newly released RCMP court documents reveal more details about the efforts made by the Prime Minister's Office and two key Conservative senators to contain fallout from a growing expense scandal in 2013 and to protect now suspended Senator Mike Duffy.

The affidavits filed in court include an email from Prime Minister Stephen Harper's then chief of staff, Nigel Wright, that outlines moves to prevent Duffy from "going squirrelly" as external auditors were called in to take a closer look at his and other senators' expenses.

The court documents include interviews between RCMP investigators and Senate administrators Jill Anne Joseph, director of internal audit, and Gary O'Brien, the now retired clerk of the Senate.

The Senate officials were asked about the PMO's influence on Senate reports written in May 2013 in response to audits of senators Patrick Brazeau, Mac Harb and Duffy done by the firm Deloitte.

Joseph also offered details about her interaction with senators Carolyn Stewart Olsen and David Tkachuk and their involvement in altering the report on Duffy. Stewart Olsen and Tkachuk were on the steering committee that oversaw the reports.

Duffy has pleaded not guilty to 31 charges of fraud, breach of trust and bribery related to expenses he claimed as a senator and later repaid with money from Wright, the prime minister's former chief of staff.

Changes to Senate report

Stewart Olsen "wanted more deletions from the report," Joseph told the RCMP, adding the "report, to my mind, was becoming very scant."

Joseph said it was her understanding that senators Tkachuk and Stewart Olsen "sort of insisted with the Senate clerk" that changes be made.

She also described how Tkachuk came to her office saying he and Stewart Olsen would like two more changes to the report, including deleting the conclusion that Duffy's continued presence in Ottawa did not support his declaration of primary and secondary residence.

Joseph also told the RCMP about discussion with Stewart Olsen over a separate, still-unreleased Senate report from February 2013 on senators' residency qualifications. Joseph said Stewart Olsen's objective "was not to get to the truth of the matters and deal with them the way I wanted to deal with them."

Duffy's defence lawyer Donald Bayne wants that Senate residency report entered as evidence in Duffy's trial. It was Bayne's motion to include the Senate residency report that prompted the release of the RCMP affidavits.

Residency is one of the central issues in the case against Duffy. He designated his home in P.E.I. as his primary residence, making him eligible to claim meals and living expenses for his time in Ottawa, even though he has lived and worked in Canada's capital since the 1970s. The Crown in Duffy's trial disputes that P.E.I. is his primary residence.

Plan to prevent Duffy 'from going squirrelly'

During the course of the interviews, the RCMP also cited a February 2013 email from Wright that said he had been on the phone with Duffy, Tkachuk and Senator Marjory LeBreton, the former government leader in the Senate.

According to ​Wright's email, the plan was to announce in a statement that the expense cases of Harb, Brazeau and Duffy were being referred to an external auditor — but at same time issue a separate release stating external legal advice was being sought on the meaning of primary residency.

"A purpose of this is to put Mike in a different bucket and to prevent him from going squirrelly in a bunch of weekend panel shows," Wright wrote.

Joseph also told RCMP investigators there had been discussion at one point about going "directly to the police" about the Duffy matter.

She said Liberal Senator George Furey felt "we shouldn't just fool around with this" and that police were best placed to decide the matter.

But, Joseph said, there was also a feeling that "before we refer things to police we do an internal investigation into this thing."

In question period today, Opposition NDP Leader Tom Mulcair took aim at the Conservative government over the newly released documents.

"This is pure Richard Nixon," Mulcair said. "The Duffygate coverup was orchestrated right in the Prime Minister's Office, that's what these RCMP court documents prove — why won't the prime minister answer?"

Paul Calandra, parliamentary secretary to the prime minister, said the government won't comment on a matter before the courts.