New court documents have shed more light on how staffers in the Prime Minister鈥檚 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鈥 interviews with a former Senate clerk and an administrator, the prime minister鈥檚 former chief of staff, Nigel Wright, and others discussed Duffy鈥檚 problematic expense claims by email in 2013.

In one email sent in February of that year, Wright wrote that the Senate had requested 鈥渆xternal legal advice鈥 on Duffy鈥檚 residency issues.

鈥淭he 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,鈥 Wright allegedly wrote in the email.

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

At that time, the Senate committee was preparing reports based on Deloitte audits of several senators鈥 -- including Duffy鈥檚 -- 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鈥檚 disputed expense claims. After the arrangement was publicly revealed, Wright left the PMO. He will testify in Duffy鈥檚 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鈥檚 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鈥檚 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鈥檚 involvement in the Duffy scandal. 

鈥淭he Duffygate cover-up was orchestrated right in the prime minister鈥檚 office. That鈥檚 what these RCMP court documents prove,鈥 he said.

Stephen Harper鈥檚 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