OTTAWA — The lawyer leading the robocalls election case acknowledged Tuesday that he faces a challenge proving voters were disenfranchised without evidence that “there are ballots that aren’t in the ballot box.”

Steven Shrybman, the lawyer for eight voters who want the Federal Court to overturn the election results in six ridings, told Judge Richard Mosley that he is “up against the difficult task of proving the negative.”

But Shrybman said the evidence shows that people across the country were stopped from voting by misdirecting or harassing calls.

He urged the judge to consider the numerous complaints described in internal Elections Canada emails, and others itemized in sworn statements from agency investigators, that detailed alleged voter-suppression calls reported in more than 240 ridings.

“There is no loaded gun,” he admitted. “We have not been able to adduce for this court electors who didn’t vote, let alone large numbers of them.”

Instead, Shrybman said the judge should consider similar stories from voters across the country that are consistent with those in the six cases before the court.

“It’s all of a piece,” he said.

Shrybman pointed to a voter in the Quebec riding of Rivière-du-Nord — not one of the ridings at issue — who complained to Elections Canada that he received three automated calls telling him his polling station had changed and who ultimately did not vote in the May 2, 2011 election.

This complainant, whose name was redacted from court documents, is the first on the public record to say his franchise was affected by a misleading call, although an Elections Canada investigator has reported that some voters in Guelph tore up their voting cards in frustration when directed to the wrong poll.

For months — and as recently as during question period on Monday — the Conservatives have rebutted allegations about the robocalls scandal by claiming not a single person lost his or her franchise.

But to Shrybman, there is clear evidence of a countrywide effort to discourage voters.

“A person or person unknown engaged in fraudulent activities intended to affect the results of the election in the six electoral districts at issue,” Shrybman told the court.

“A direct assault has taken place on the first building block of the democratic society, the right to vote.”

To prove that, he said, it is not necessary to show who carried out fraudulent activities, merely that they took place.

“We don’t know who engaged in those activities and we are not accusing the Conservative Party of Canada of conspiring to defraud Canadian electors,” he said.

Shrybman took the judge through court documents from Elections Canada’s investigation of voter-suppression calls, starting with the investigation into the robocall that send hundreds of voters to the wrong polling station in Guelph.

He characterized the efforts of the suspect identified as Pierre Poutine as “a clandestine and covert act to suppress the vote.”

The suspect went to great lengths to disguise his or her identity, using a disposable “burner” cellphone, untraceable credit cards and a proxy server to disguise the Internet Protocol, Shrybman said.