Prime Minister Stephen Harper’s ex-chief of staff worked closely with two Conservative senators to persuade Sen. Mike Duffy to pretend to repay $90,000 in invalid expenses with his own money, emails show.

The emails, seen by CTV’s Ottawa Bureau Chief Robert Fife, reveal that Harper’s former right-hand man, Nigel Wright, consulted with David Tkachuk and Carolyn Stewart Olsen – two senators who were overseeing what was supposed to be an independent audit of Duffy’s expenses.

In May, Fife revealed that Wright had personally bailed out Duffy by writing him a $90,000 cheque to cover his improperly claimed expenses. Harper and his office have insisted that Wright acted alone, but the latest emails suggest otherwise.

Those emails show that Duffy had initially refused to go along with the plan to repay the taxpayer-funded living allowance and other expenses using Wright’s money.

The embattled senator was then threatened with the loss of his seat in the upper chamber.

In the emails, Duffy claimed that Tkachuk, who until recently was the chair of the Senate internal economy committee, told him he didn’t meet the Senate’s residency requirements because he lived in Ottawa.

Duffy, who represents Prince Edward Island in the Senate, did not have a valid P.E.I. health card and was not on the voters’ list in that province in 2011. Property tax records also showed that Duffy and his wife were considered non-resident owners of their P.E.I cottage.

Tkachuk allegedly told Duffy that if he went along with Wright’s bailout offer, the Senate committee would throw out the residency issue and go easy on him in the audit of his expenses.

Tkachuk did not return phone calls seeking comment.

In one email, Duffy says Wright called him on Feb. 19, promising to pay off his debt to taxpayers and offering cash for the repayment.

Wright resigned from the Prime Minister’s Office after his cheque to Duffy came to light.

Harper’s former director of communications, Angelo Persichilli, was also putting pressure on Duffy amid the growing Senate spending scandal.

While Persichilli was awaiting his appointment as a citizenship judge in Toronto, he called Duffy to tell him that the Conservative Party would turn against him if he didn’t repay the money.

Persichilli insisted he acted alone and as a friend when he made that call.

“I was urging him to give the money back, but as a friend,” he told CTV News. “Never, never was I told by anyone from the PMO that I had to talk to Mike Duffy.”

Duffy left the Conservative caucus in May, saying the controversy surrounding him had become a “significant distraction” to his colleagues and the government.

The RCMP is investigating the expense claims filed by Duffy, as well as Sen. Patrick Brazeau and Mac Harb, a former Liberal senator who announced his resignation Monday.

The Senate also recently referred the audit of Sen. Pamela Wallin to the RCMP.