I might start looking closely at all three HarperCon won elections and combing through the complaint files.
Harper has had one immediate goal for his party since taking the helm: Majority. He failed to achieve that end in 2006 and failed again in 2008 because Canadian voters got in the way. Issues around the results of the latter of those elections are now reemerging in light of the growing election fraud scandal.
If the Conservatives engaged in questionable practices on a limited scale at least in 2008, and got away with it, then it more than possible they'd do it again.
They'd even have incentive to kick it up a notch in 2011 if they felt that they were in for another round of minority purgatory. I also don't imagine Harper would have lasted much longer at the helm if that were the outcome...
I believe the police and Crown call this sort of stuff 'motive'.