With his client on the witness stand, Dean Del Mastro's lawyer is systematically attacking the allegations of election-campaign overspending that have been levelled against the Peterborough MP.
Del Mastro has already said he never asked an Ottawa data-consulting firm for voter identification calling services during the 2008 federal campaign – services that allegedly pushed him past campaign spending limits.
He spent the morning describing the breakdown of his relationship with Frank Hall, the president of Holinshed Research, whose testimony has been a key part of the Crown's case.
And he's denying that he ever received or replied to a series of incriminating emails produced by the Holinshed president.
Del Mastro – once the Harper government's chief defender against partisan claims of voter fraud, now an Independent MP – says he made a personal payment to Holinshed in 2008 for riding mapping software being developed by Hall's company.
The Crown alleges that the payment was for Holinshed's supposed voter identification calling services –a payment which would have exceeded a limit on personal contributions.
The Crown has also alleged Del Mastro tried to use backdated invoices to make it appear Holinshed had only charged a fraction of the overall cost during the election period – an allegation the MP denies.
Del Mastro is also suggesting that emails Hall provided to investigators, allegedly detailing discussions between the two, are fake.
"So that email chain...you just say you didn't write those, you didn't receive those?" asked defence lawyer Jeffrey Ayotte.
"This electronic discussion did not take place," Del Mastro replied. "I did not write them, I did not receive them."
Del Mastro has pleaded not guilty to charges of overspending during the 2008 campaign, failing to report a personal contribution of $21,000 to his own campaign and knowingly submitting a falsified document.
He left the Conservative caucus in September 2013 and has maintained his innocence throughout the trial, which is now in its third week.