The allegations are spelled out in documents seeking a court order to compel the companies on whose boards Wallin used to sit to produce all documentation related to her expenses.
The documents, filed by Cpl. Rudy Exantus in late January and publicly released Monday, allege that the disgraced Conservative senator defrauded the Senate by making 150 "suspicious" expense claims.
No charges have yet been laid against Wallin, who was suspended from the Senate last year, and none of the allegations has been proven in court.
Among the suspicious expenses were claims for 24 events Wallin attended in her capacity as a member of the boards of Porter Airlines and Gluskin Sheff. The RCMP alleges that Wallin fraudulently received almost $27,500 in Senate reimbursements for those meetings.
Wallin's lawyer, Terrence O'Sullivan, said expense claims for those meetings were inadvertently submitted to the Senate, instead of to the companies, due an "administrative oversight." Wallin, who has reimbursed the Senate for more than $150,000, was not trying to pad her own pockets since she would have been reimbursed by Porter and Gluskin Sheff in any event, O'Sullivan said.
Wallin explained all that to external auditors hired by the Senate to review her expenses and they concluded there had been no fraud, O'Sullivan added.
O'Sullivan could not, however, immediately explain other allegations contained in the court documents.
The Mounties allege Wallin filed an expense claim for an eco-cardiogram at the Peter Munk Cardiac Centre at Toronto General Hospital in March 2010.
She described the meeting to external auditors as a meeting with Peter Munk, founder and chairman of Barrick Gold, "for a briefing on the state of his industry and to discuss Canada-U.S. relations."
However, Munk told the RCMP he was in Switzerland at the time and did not meet with Wallin, although he could have talked to her by phone.
The documents also allege that Wallin filed an expense claim for a Toronto meeting with Michael Decter in February 2010. She told the external auditor that Decter was an investment manager, Harvard-educated economist and "leading Canadian expert on health systems" whom she met to discuss "business, finance and health care issues, specifically the federal government's role."
She further told the auditor that Decter wanted to talk to her about a "funding issue."
However, Decter told the RCMP that he used to be in an "intimate relationship" with Wallin, which had ended a decade earlier, although they remain friends and get together half a dozen times a year, usually for dinner. He said they have wide-ranging conversations "about the world."
He had no recollection or records to confirm the particular meeting for which Wallin filed an expense claim with the Senate.
The documents include summaries of police interviews with people who organized various Toronto events for which Wallin filed expense claims. In several instances, there was no evidence Wallin attended those events but the police did find evidence she'd actually been at other events for Porter, Gluskin Sheff or the University of Guelph, where she was chancellor.
"Sen. Wallin, when confronted by an external audit, misrepresented the nature of these trips to Toronto, and at time (sic), fabricating meetings which the RCMP was able to determine (through interviews) to have never taken place," Exantus says in the documents.
He adds that he believes her conduct represents "a serious and marked departure from the standards expected of a Canadian senator."
The Mounties have been investigating Wallin for 18 months.
They have already charged two other Conservative senators, Mike Duffy and Patrick Brazeau, and one retired Liberal senator, Mac Harb, with making fraudulent expense claims. All three maintain their innocence.
Duffy's trial begins April 7.
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