The Crown prosecutor is going after serious prison time in the Guelph, Ont., robocalls case, choosing to pursue Michael Sona for an indictable offence over misleading phone calls in the last federal election.

Sona, 24, is the only person charged so far in a broad investigation into complaints of misleading or harassing phone calls, allegedly intended to drive supporters of opposition parties away from the polls during the 2011 federal campaign.

Croft Michaelson, the federal lawyer leading the case for the Public Prosecution Service of Canada, confirmed to CBC News that the office wants to "proceed by indictment" against Sona.

Sona is charged with the hybrid offence of wilfully preventing or endeavouring to prevent a voter from casting a ballot. A hybrid offence is one where the Crown can choose to prosecute the charge as a less serious summary offence or the more serious indictable offence.

The maximum penalty for the summary conviction is a $2,000 fine and one year in jail, while the maximum penalty for the indictable conviction is a $5,000 fine and five years in prison.

Federal court found 'campaign to mislead voters'

Sona was the director of communications for Guelph Conservative candidate Marty Burke and one of a number of campaign workers mentioned in court documents filed over the past two years as Elections Canada investigators followed the trail of someone using the pseudonym Pierre Poutine to orchestrate automated phone calls that directed some Guelph voters to the wrong polling stations.

Sona started as a Conservative Party intern and worked for several MPs, including James Moore, Rob Moore and Eve Adams. He was working in Adams's office when the investigation was first reported and had to quit after his name was leaked to the media as the alleged perpetrator of the calls.

Sona has consistently denied having anything to do with the vote suppressing phone calls.

The calls in Guelph weren't the only ones to target voters.

A Federal Court judge ruled in May that voter suppression calls were widespread across the country. Judge Richard Mosley made the ruling after a court challenge that could have removed seven Conservative MPs from their seats. The MPs were challenged by voters in their ridings who alleged the MPs benefited from the pattern of harassing and misleading calls

Mosley said he was not making a finding that the Conservative Party, its candidates or the suppliers providing live and automated robocalls were directly involved in "the campaign to mislead voters," though he said that the most likely source of the information used to make the misleading calls is the Conservative Party's database.