An independent audit of Senator Pamela Wallin's expenses has found ineligible claims amounting to as much as $140,000, and that the number of those claims is in the hundreds, CBC News had learned.

The 95-page report currently being viewed by a Senate subcommittee also reveals the Saskatchewan senator made attempts to change her expense paperwork after the fact.

Sources tell CBC News that the audit reveals the following:

The audit flags at least $120,000 in questionable claims, with another $20,000 to be decided by the Senate committee. Wallin has already voluntarily repaid $38,000.

Almost all of Wallin's problems revolve around travel expense claims, most notably dinners and other expenses in Toronto and Guelph, where she was chancellor of the University of Guelph and where she was doing university business rather than Senate business.

Wallin made or attempted to make retroactive redactions or changes to her calendar. Of Wallin's four former executive assistants, three have told Deloitte that they know of calendar entries that were altered by Wallin.

Wallin, who has seen the audit, plans to speak to the media Monday afternoon. CBC News has confirmedWallin will pay back the entire amount she owes with interest, and that she wants to stay on as a senator. She is also expected to say the process is flawed and unfair because auditors are retroactively applying new rules.

Wallin, a well-known former journalist and anchor who helped Harper fundraise and drum up voter support during the last election, is the latest senator who has been subjected to scrutiny by the independent auditing firm Deloitte in an expense scandal that has turned out to be the biggest crisis the Senate has faced in its nearly 150-year-old history.

Members of a smaller Senate subcommittee received the audit and a briefing on its findings Monday morning, and Wallin herself was scheduled to receive a copy of it as well.

Senator Gerald Comeau, who chairs the subcommittee, told reporters before the meeting started, "Depending on what's in the report we'll make a determination at that point, if we sense that there was some kind of a breach, it could go to the RCMP."

Asked if the subcommittee might soften its tone in its own report due to the fact that Wallin has already repaid $38,000, Comeau replied, " I would not expect so but we'll see."

The audit will be released to the full Senate committee of internal economy later in the day and auditors will be on hand to brief the senators who sit on that committee.

The subcommittee will deliver its report, which will contain its recommendations, on the audit on Tuesday and are expected to make their report public. The Deloitte audit will also be made public.

Much of the content expected in the Deloitte report has already been flagged by one of the auditors conducting the examination and by Wallin herself.

The focus of Wallin's audit will centre on her travel expenses, specifically flights she charged to the Senate. That's what she told host Peter Mansbridge of CBC-TV's The National in an exclusive interview that aired in June. Any issue over her expenses, she said, is about "flight costs. Flight costs. So, money is not in my pocket, the money is in the pocket of the airlines."

Wallin told Mansbridge that Senate paperwork is so onerous it's as if it were not "humanly possible to keep on top of. So I made mistakes."

Auditors leave a meeting Monday morning after briefing members of the Senate subcommittee looking into Senator Pamela Wallin's expense claims. (Margo McDiarmid/CBC)

She said that as she re-examined her expenses paperwork with the help of her two Senate assistants, she realized some of her airline tickets charged to the Senate should have been paid for by what she called a "third party," which she said was "more like a board than an event."

Wallin sat on at least three boards for most of the time she's been in the Senate, including Porter Airlines and the investment firm Gluskin, Sheff. She's since resigned from those positions.

Until 2011, she was also chancellor of the University of Guelph. In March the Guelph Mercury reported Wallin claimed nearly $25,000 in expenses during the four years she served as chancellor. The newspaper quoted a university spokesperson, Chuck Cunningham, who said Wallin's expenses were lower than other chancellors because she usually stayed at a suite in the university residence rather than at a hotel when she attended events.

A copy of Wallin's expense claims, released by the university to CBC News, shows that during the period in which she was a senator, Wallin charged for airline travel only during her final year as chancellor. For most years, her claims were for "non-airfare travel", and she never billed for hospitality expenses.

Wallin told Mansbridge she had voluntarily paid back $38,000 to the Senate, and admitted she might owe more.

Stopovers on the way to Saskatchewan

Wallin also told Mansbridge that the reason her travel claims to the place she calls her home — Saskatchewan — seem so low over a two-year period compared with the $300,000 claimed for other travel is that she often stops over in Toronto on her way back to her native province.

"If I have a day like a Friday where I can go to Halifax or Edmonton or Toronto and do a speech or do an event, I will do that on the way home. I am still going home. That doesn’t count as travel to my home. It counts as 'other.'"

Wallin said that flights to Saskatchewan from Ottawa are long and infrequent, and although an airline ticket might appear to be for an Ottawa-Toronto route, the final destination could be Saskatchewan.

Although Wallin owns a condo in Toronto, she said she spent 168 days at her home in Wadena, Sask.

Wallin, appointed by Prime Minister Stephen Harper as a Conservative senator, now sits as an Independent.

Wallin's audit was extended twice

Something about the pattern of Wallin's claims, however, must have been red-flagged by the Senate's administration. Deloitte has been asked twice by Senate staff to extend the audit period for Wallin's claims, which at first covered an 18-month period. The audit now begins when she was first appointed to the Senate at the start of 2009.

The Deloitte audit has been underway for over six months, and in June a Deloitte auditor appeared before a Senate committee to explain the delay.

In a rare 15-minute period when the normally secretive committee of internal economy allowed the public to listen to testimony from one of two auditors working on Wallin's case, Gary Timms explained that the "lens" he was using was different from the one employed with three other senators.

In the cases of senators Mike Duffy, Patrick Brazeau and Mac Harb, the Deloitte audits examined how much time the senators spent in homes they claimed were their primary residences as opposed to days spent in Ottawa.

In Wallin's case, Timms said, the focus is "more on the nature of the expenses and whether they were Senate business expenses."

In the other three cases, the RCMP has filed court documents revealing the force suspects Duffy, Harb and Brazeau of filing inappropriate expense claims contrary to the Criminal Code. No charges have been laid and none of the allegations have been proved in court.

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