Dean Del Mastro is on the defensive as he endures a full day of cross-examination at his election overspending trial in Peterborough, Ont.

Crown lawyer Tom Lemon is casting doubt on the MP's claim that a personal cheque written to data-consulting firm Holinshed Research was a deposit on riding mapping software called GeoVote.

The Crown alleges Del Mastro made the personal payment to the company not for GeoVote, but for voter identification calling services provided during the 2008 federal election campaign.

The cheque for $21,000, if indeed meant for voter ID services, would have pushed Del Mastro over his campaign spending and personal contribution limits.

Lemon is suggesting it's unusual that the cheque, dated August 2008 before the campaign period, was picked up by a courier and cashed in October — during the campaign — just hours after enough money to cover it was transferred into Del Mastro's account.

Lemon also says bank records show Del Mastro's bank card was used to make the transfers, but the MP says he doesn't remember making them.

Del Mastro says his wife has access to his cards and accounts and does all the family's personal banking.

He admits he doesn't have any direct knowledge of how the cheque was cleared but has said his bank account was tied to a personal line of credit.

He says a financial adviser could have called his wife, and asked her to deposit sufficient funds before the cheque cleared.

Lemon, however, said Del Mastro's explanation was speculation.

"This speaks for itself," he said. "There's a transaction record of a deposit at 12:29 p.m. roughly three hours after you or someone transferred the amount into your account."

"I'd like to tell you how that happened," Del Mastro offered.

"Do you have any direct knowledge?" asked Lemon.

"No sir, I don't," Del Mastro replied.

Get-out-the-vote calls

Del Mastro is charged with overspending during the 2008 federal election campaign, failing to report a personal contribution of $21,000 to his own campaign and knowingly submitting a falsified document. He has denied all the allegations.

The MP, who now sits as an Independent, has said he never contracted Holinshed for voter identification calling services during the 2008 campaign, even though the firm's president, Frank Hall, has testified that hundreds of hours of calls were made.

Del Mastro has said the only campaign-related contract he had with Holinshed was for a portion of get-out-the-vote calls to be made on election day, which were declared in his campaign expenses.

For those services, Del Mastro said his campaign had transferred voter information data to Holinshed in mid-September.

But Lemon took issue with the timing for that exchange, which was weeks before election day.

"I would suggest to you that if you're providing information on get out the vote only, you're not doing it on Sept. 15, a month before the election," he said.

"You can suggest that, but in fact that's not what was done," Del Mastro responded.

If found guilty, Del Mastro could face a fine of $1,000 and a year in jail, but would not be barred from running for office again.