Harper's former chief of staff, Nigel Wright, has borne the full blame of his ex-boss for the controversial scheme to reimburse the disgraced senator's $90,000 worth of disallowed expenses. Wright resigned in May.
But other senior staff in the Prime Minister's Office, including director of issues management Chris Woodcock and manager of parliamentary affairs Patrick Rogers, were also active in the discussions about how to get Duffy to repay his expenses.
Both are still with the government: Woodcock works for Natural Resources Minister Joe Oliver, Rogers for Heritage Minister Shelly Glover.
The deal originally involved the party reimbursing Duffy for repaying his expenses, while curtailing an audit into his claims. Conservative Fund chairman Irving Gerstein was also aware of the talks, and he solicited information from a contact at auditing firm Deloitte about the status of their report.
"The question is, why he hasn't fired all these other people in his office who were part of this coverup?" NDP Leader Thomas Mulcair demanded Tuesday during question period.
Liberal Leader Justin Trudeau continued in a similar vein: "Will the prime minister please explain to Canadians why Sen. Irving Gerstein continues to enjoy his complete confidence?"
Harper has steadfastly maintained that only two people are responsible for possible wrongdoing: Wright and Duffy. The RCMP has alleged they committed fraud, breach of trust and bribery in striking the deal that involved the exchange of money.
No one has been charged.
"The RCMP has said that there are two people under investigation," Harper said.
"When the leader of the Opposition starts tarnishing the names of people who face no allegations whatsoever, I am reminded, once again, of the old saying, 'When you throw mud, you lose ground."'
Gerstein's involvement is likely to come up on Thursday when the Senate internal economy committee recalls auditors from Deloitte.
A March 21 email exchange inside the PMO suggests staff were privy to details about the audit a full month before the committee's three-member steering group received an interim briefing from Deloitte on the process.
Police also heard that at different junctures, the two Conservatives on that steering group tried to halt the audit.
Liberal Sen. George Furey, the third member of that original steering group, said he's going to ask the chairman of the internal economy committee to make Thursday's meeting with Deloitte accessible to the public.
"There were certain allegations set out in (the RCMP documents) that raise a number of questions we'd like to ask the auditors," Furey said.
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