A $600-a-plate fundraiser for then-Conservative MP Dean Del Mastro's Peterborough riding association brought in just a little more than half the amount originally reported to the press, according to financial records filed with Elections Canada.

That's despite a headline performance by former prime minister Brian Mulroney at the dinner held at Toronto's swanky Albany Club.

The May 2, 2013 event at the private Toronto club was more than just an attempt to fill the local Conservative coffers.

It was also viewed as a show of support for Del Mastro, who at the time was under investigation over expenses related to his 2008 election campaign.

And it's not clear where that money was spent.

The Peterborough Examiner reported that riding association president Alan Wilson said "about 120 people" had attended the speech.

Given the $600 ticket price, that should have resulted in a net haul close to $72,000, depending on how many paid full price for the chance to hear Mulroney speak.

Several high profile reported attendees not on donor list

But in its 2013 financial statement, the Peterborough Conservatives reported total revenue of $41,300 for the entire year.

Although the contributor list isn't broken down by event, by cross-referencing the dates and amounts, it would seem the Mulroney event actually pulled in just $39,310 from fewer than 75 ticket-holders — including a $1,030 contribution from the former prime minister himself.

Among those recorded as making a donation to the association on or around May 2, the date of the Mulroney speech:

Retired Conservative senator David Angus, appointed to the Upper House by Mulroney in 1993 ($515 on May 2)

William Pristanski, Mulroney's former executive assistant, now a lobbyist at Prospectus Associates ($515 on April 30)

Investment adviser Andrew Lapham, married to Mulroney's daughter Carolyn ($1,030 on May 2)

Globalive chairman Tony Lacavera ($1,030 on May 2)

Vaughan developer Mario Cortelucci ($1,200 on May 2)

Ex-NHL goalie Paulo Colaiacovo ($1,030 on May 1)

As demonstrated above, a good number of contributors seem to have purchased two tickets to the event, although the names of their guests are not recorded.

Several high-profile Conservatives who were initially reported to be at the event are conspicuously absent from the list of contributors, however, including Employment Minister Jason Kenney and Haliburton-Kawartha Lakes-Brock MPP Laurie Scott.

A spokesperson for Kenney's office confirmed that the minister was there, but couldn't say whether he had purchased a ticket, as he had also been scheduled to speak, which would likely have waived the cover charge.

Scott, who is currently running for re-election in the Ontario race that ends June 12, did not respond to a request for comment.

Another reported attendee, Kawartha Lakes Mayor Ric McGee, came under fire when it was revealed that he had billed his ticket to the municipality. After those payment details went public, the riding association reportedly refunded the money, although it doesn't appear in the filing, which includes a special section for contributions returned to donors.

Attendance report 'inaccurate': Riding president

In response to a query from CBC News, riding association president Alan Wilson said the original media report on attendance at the event was "inaccurate," although he declined to provide his own crowd estimate.

He didn't respond to a follow-up query on whether any of the funds raised at the Albany Club event had been used to defray Del Mastro's legal expenses.

In a post-event interview with Peterborough Examiner reporter Brendan Wedley, Wilson had indicated that it was "a hypothetical situation," but acknowledged that it was possible.

"There hasn't been a request up to this point," he told the paper.

Since then, Del Mastro has been formally charged with several offences under the election laws, including deliberately filing a false or misleading report, donating more than the allowable amount to his own campaign and exceeding the election spending limit.

None of those charges have been proven in court, and the case is expected to go to trial later this summer.

As soon as he became aware of the charges, he voluntarily left the Conservative caucus to sit as an independent until the matter is resolved.

Del Mastro's brother, staffer on riding executive

His current status with the riding association of the party he no longer officially represents, however, is less clear.

Last year, the Peterborough association reported spending $43,806.00 on otherwise unspecified "professional services," which could include, among other things, legal fees.

That not only represents a significant jump from previous years — between 2007 and 2012, the same category accounted for just $6,000 in total expenditures, with no more than $1, 637 in related charges reported in a single year — but comes out to slightly more than the total reported revenue for 2013.

Neither Wilson nor the Conservative Party responded to a query on whether any of those "professional services" related to Del Mastro's legal expenses.

Del Mastro's office referred CBC News to his lawyer, Jeffrey Ayotte, who cited solicitor-client privilege, and declined to answer the question.

There are no rules that would prevent the riding association from helping Del Mastro with his legal bills, but it would be unusual for it to do so on behalf of an MP not currently formally affiliated with the party.

According to the association website, his brother, Doug Del Mastro, sits on the executive, as does his constituency office "outreach coordinator" Ashley Moore.

Riding officials have also reportedly put the nomination process on hold pending the outcome of Del Mastro's case.