New court documents have shed more light on how staffers in the Prime Minister’s Office and two Conservative senators tried to protect Mike Duffy in the early days of the Senate expenses scandal.

According to transcripts of RCMP investigators’ interviews with a former Senate clerk and an administrator, the prime minister’s former chief of staff, Nigel Wright, and others discussed Duffy’s problematic expense claims by email in 2013.

In one email sent in February of that year, Wright wrote that the Senate had requested “external legal advice” on Duffy’s residency issues.

“The purpose of this is to put Mike in a different bucket and to prevent him from going squirrely in a bunch of weekend panel shows,” Wright allegedly wrote in the email.

“Mike is very pleased with this so it will give us a little bit of time if David can pull it off,” he allegedly wrote, referring to Sen. David Tkachuk, who was the chair of the Senate’s Internal Economy Committee at the time.

At that time, the Senate committee was preparing reports based on Deloitte audits of several senators’ -- including Duffy’s -- expenses.

Duffy is on trial in Ottawa on 31 counts of fraud, breach of trust and bribery related to his living and travel expenses. He has pleaded not guilty to all charges.

In 2013, Nigel Wright wrote Duffy a personal cheque in the amount of $90,000 to cover the now-suspended senator’s disputed expense claims. After the arrangement was publicly revealed, Wright left the PMO. He will testify in Duffy’s trial.

According to the newly released documents, Senate administrator Jill Anne Joseph told RCMP investigators that Tkachuk and Sen. Carolyn Stewart Olsen were involved in redacting the audit of Duffy’s expenses.

Joseph, a senior audit adviser, also said that she told a special Senate audit subcommittee that there was a lack of clear criteria around residency, but her opinion was dismissed.

The new court documents were filed by Duffy’s lawyer Donald Bayne, who is seeking to obtain certain reports and documents the Senate does not want released, citing parliamentary privilege.

NDP Leader Thomas Mulcair raised the documents during question period Thursday, demanding answers about the PMO’s involvement in the Duffy scandal. 

“The Duffygate cover-up was orchestrated right in the prime minister’s office. That’s what these RCMP court documents prove,” he said.

Stephen Harper’s parliamentary secretary, Paul Calandra, only said that the Duffy case is before the courts and that the government continues to work with the Crown.

With files from CTV's Philip Ling in Ottawa and The Canadian Press