The PMO denied Wednesday that it is withholding the email, which apparently summarizes the deal struck between Sen. Mike Duffy and Harper's chief of staff, Nigel Wright, to pay off invalid expense claims.
"Contrary to CTV's reporting, our office has not been asked for this email," spokesperson Julie Vaux said in an email statement.
"As we have always said, we will assist investigations into this matter."
However, Vaux refused to say whether the RCMP has asked for other emails or documentation regarding the $90,000 cheque Wright wrote to Duffy or whether the Mounties have interviewed anyone at PMO.
RCMP spokesperson Cpl. Lucy Shorey also declined comment.
"We're not in a position to comment on the matter because it is an ongoing investigation."
According to a CTV report Tuesday, the Feb. 20 email from Duffy to his lawyer — and possibly copied to Wright — summarized the deal between the two.
It said Wright would give Duffy $90,000 to repay his invalid expense claims, that Duffy would claim to have personally reimbursed the Senate and the government would use its influence to soften the impact of an external audit into Duffy's expenses.
In May, shortly before news of the secret transaction broke, a Senate committee report on the audit was amended to be less critical of Duffy, compared with reports on two other senators whose own expenses were also under fire.
Wright resigned five days after word of his payment to Duffy leaked out.
CTV says it has been contacted twice by the RCMP about the email and, in order to protect its sources, advised the Mounties to seek it from the Prime Minister's Office.
Reg Whitaker, University of Victoria professor emeritus who has studied and written about the history of the RCMP, said the pressure on police to obtain the email will increase now that the word is out that it hasn't yet asked the PMO for it.
It would be best for all concerned for the email to be produced voluntarily, without the necessity of a production order or search warrant, he added.
While the Mounties would be reluctant to get into a legal shoving match with PMO, Whitaker said, it's not in the government's interests to "bring out its battery of lawyers to block the production of something that clearly is in the public interest."
Whitaker said he's unaware of any instance in the history of the RCMP when it had to resort to legal instruments to compel criminal evidence from a sitting prime minister or his office. Nor could he think of any justification the PMO could use for obstructing the investigation.
"It's not Watergate or something like that where they're claiming national security."
Rob Walsh, a former parliamentary law clerk whose recent retirement has freed him to comment extensively on Commons legal issues, took to Twitter on Wednesday to explain the protections prime ministers have from criminal investigations.
"There's no legal privilege attached to PMO except cabinet confidences and 'official secrets' under the Evidence Act," Walsh wrote — neither of which would appear to apply in the Wright-Duffy matter.
One person familiar with investigative procedures suggested the RCMP would try the easiest means of getting a particular document — simply asking for it — before resorting to a production order or search warrant.
The Mounties may be waiting to present PMO with a complete list of documents they want instead of going about it in piecemeal fashion and tipping their hand as to what they're interested in, said the individual, who asked not to be identified due to the sensitivity of the matter.
However, that would not preclude RCMP officers from using legal instruments later, said the person.
"If they believe they have a tool and they believe they need it, very few of them will hesitate to use the tool if it gets them closer to getting to the truth in the context of an investigation. So at this point it's probably not the tool of choice."
The Mounties have interviewed at least three senators on the matter — Marjory LeBreton, government leader in the Senate at the time; Carolyn Stewart Olsen, one of two Conservative senators responsible for amending the initial report on Duffy's expenses; and Liberal George Furey, who objected to the amendments.
LeBreton said she was interviewed on July 3, one day before she announced her previously made decision to resign as the government's Senate leader.
"I fully co-operated," she said in an email.
As for the elusive email, LeBreton said: "I have no knowledge of it, other than what has been reported in the media."
Stewart Olsen was interviewed in late June. She also said she knows nothing about the email.
— With files from Bruce Cheadle and Jim Bronskill
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