Dean Del Mastro, the Peterborough, Ont., MP and former parliamentary secretary to Prime Minister Stephen Harper, will seek to clear his name in a trial that starts today in his hometown.

Del Mastro and his official agent, Richard McCarthy, face charges of overspending their 2008 election limit, knowingly misleading Elections Canada by reporting a $21,000 expense as an expense of $1,575 and not providing the agency with the information it requires. Del Mastro also faces a charge of purposely exceeding his personal donation limit.

Del Mastro says he ran a clean campaign and did nothing wrong. He didn't respond to an emailed request for comment but has repeatedly told CBC News Network's Power & Politics that he expects to be cleared.

Crown lawyer Tom Lemon told the court Monday morning that the case might be considered unusual.

Lemon says a large documentary record and several witnesses will be involved in the trial.

The trial will have to sort through a maze of project estimates, invoices and emails that paint a confusing picture of more than two years of business dealings between Del Mastro and Frank Hall, a pollster who once worked for then opposition leader Preston Manning.

The prosecutor's case will rely in part on Hall's testimony. He may be the first witness called in the case that's scheduled to run for just under three weeks.

Contradictory invoices, interviews

Much of the investigation, according to court records, has been about piecing together the sometimes contradictory series of invoices, interviews, riding association records and hundreds of emails to sort through which contracts actually existed and what payments were made. The investigators also looked at electronic document metadata to determine whether they were backdated.

The trial that starts today may not be the only controversy Del Mastro faces: Elections Canada is also probing allegations that his cousin, David Del Mastro, paid for 22 people to donate to Del Mastro's election campaign to get around donation limits. Dean Del Mastro was not the subject of the search warrant that was made public last January.

The investigation that led to this trial started in April 2011, after Hall approached Elections Canada.

Hall, according to court records, complained to the agency after seeing the wrong cost for his services show up on Del Mastro's campaign filing (candidate filings are posted online). Hall said that he'd asked the campaign to correct the filing, but that McCarthy responded by saying most of the $21,000 was for a contract with the riding association and that only $1,575 had been for the election campaign.

Del Mastro told investigators that cheque was a deposit for other services provided outside of the election period.

​Hall tried to sue Del Mastro in 2009 over work for which he says he wasn't paid, but let the lawsuit lapse.

Personal cheque at issue

Elections Canada investigators allege in court records that Del Mastro's campaign hired Hall's company Holinshed to provide $21,000 in voter identification and voter contact services during the election campaign held in the fall of 2008, and that Del Mastro wrote a personal cheque to cover the cost of the services. Candidates are allowed to contribute a maximum of $2,100 to their campaigns, which would make the alleged personal payment 10 times what Del Mastro was allowed to contribute to his campaign.

The $21,000 fee also would have put Del Mastro over his campaign spending limit.

Del Mastro's campaign reported a $1,575 cost for Holinshed's services. Elections Canada said in court documents that investigators believe Del Mastro knew he'd spent too much and tried to cover it up through a series of false invoices. The agency's investigators also said in court filings that they believe McCarthy knew Del Mastro spent too much but submitted an erroneous election claim anyway.​

Del Mastro stepped down from the Conservative Party caucus last fall when Elections Canada announced the charges against him.