OTTAWA—Federal elections investigators are probing robo-calls in another riding — Nipissing-Temiskaming in northern Ontario — that could have tipped one of the tightest races in the country in favour of the Conservative party, the Star has learned.

In the week before Election Day, an automated voice message was received by a North Bay environmental activist that raised her suspicions.

“I got a call that said it was Elections Canada calling to say that due to higher than anticipated voter turnout that my polling place was changed,” said Peggy Walsh Craig.

In an interview with the Star, the woman said she had received two calls during the spring 2011 campaign, the first a few weeks before voting day on May 2. It asked if she intended to vote for the Conservative party. She did not. The second came in the week prior to the election.

Walsh Craig recalled wondering how did Elections Canada get her phone number, and how would it know voting turnout was high in the days before the election. She did not know at the time that the telephone call she described as “really strange” would be replicated in households across the country.

Elections Canada — which says it does not have voter telephone numbers and does not call individual voters — said it has been flooded with complaints about suspicious calls telling voters their polling booth had been changed.

Over the weekend, investigators with the Commissioner of Canada Elections contacted Walsh Craig to review her complaint.

Her account of the fraudulent call to Ottawa-based investigator Tim Charbonneau is particularly important in a riding where the incumbent Liberal, Anthony Rota, lost by just 18 votes to Jay Aspin, the Conservative candidate.

Charbonneau didn’t reveal the extent of the probe, but said he was working straight through the weekend to deal with what the federal election agency has said were 31,000 complaints by Canadians who believe they were subject to dirty tricks in the last campaign.

“They said there is a chance they may be back in touch with me,” Walsh Craig said. “He said he thought that my account sounded credible, for whatever that’s worth.”

The calls she describes having received are similar to those investigators have already uncovered in the ridings of Guelph and Windsor–Tecumseh that have been traced back to RackNine Inc., an Edmonton-based automated telephone service.

RackNine Inc. received thousands of dollars from campaigning Tories in 2011. The company is not reported to have worked on Aspin’s campaign in Nipissing-Temiskaming. RackNine has also denied any wrongdoing and says it is cooperating with Elections Canada’s investigators.

Aspin’s official report of election expenses only notes payments of $5,221.44 to Calgary-based Alberta Blue Strategies.

That firm is one of about a half-dozen live and automated calling services that Conservative candidates employed in the last campaign.

Alberta Blue Strategies describes itself as offering “live telephone services and political solutions” including fundraising, voter identification, polling and robo-calling.

“We are Conservatives who want to see Conservatives win,” the company notes on its website.

The governing Conservatives are shrugging off questions in the House of Commons.

On Monday, Harper was absent but his parliamentary secretary, MP Dean Del Mastro, said the Liberals were the source of their own woes, and just hadn’t accepted the results of the last election.

“The Liberals made a lot of calls in the last election and they are the source of all these complaints,” Del Mastro said. He said it was up to the Liberals to release their phone call records, not the Conservatives.

“Of all the wacko things that Mr. Del Mastro has said in the past 10 days, that has got to be the wackiest,” said Liberal interim leader Bob Rae.

Jean-Pierre Kingsley, former chief electoral officer of Canada, told the Star that if the Liberal party misdirected its own voters or made calls that harassed and annoyed their own supporters to the point they didn’t vote, “That’s called stupidity. Stupidity is not against the law.” But if another party’s callers misrepresented themselves as Liberals with the goal of dissuading others from voting Liberal, “that’s against the law,” he said.

With files from Petti Fong