OTTAWA — Move over Senate scandal: Pierre Poutine and the robocalls are back in 2014.

Former Conservative staffer Michael Sona's trial is scheduled to begin this June. Sona, Tory candidate Marty Burke's communications director during the 2011 election campaign in Guelph, Ont., was charged last April with "willfully preventing or endeavouring to prevent an elector from voting" in connection with hundreds of automated calls that sent voters to the wrong polling station.

The calls fraudulently represented Elections Canada, and many of the people who received them told investigators they had previously identified themselves as Liberal supporters to Conservative Party callers.

Sona, who so far is the only person charged in the affair, faces up to five years in prison and fines of up to $5,000.

Andrew Prescott, the deputy manager for the Guelph campaign, has been given immunity from prosecution in exchange for his testimony.

Sona insists he is innocent. In his first interview last October, Sona told The Huffington Post Canada he was thrown under the bus by party officials looking for someone to blame after the robocall story appeared in the media.

Although his trial is not scheduled to start until June 2, court documents provide a glimpse into the case against him. Sona disputes much of the evidence. He and his lawyer, Norman Boxall, declined to comment for this story.

In a recent court submission, the federal Crown attorney said Sona had repeatedly accused Elections Canada investigator Allan Mathews of incompetence and Conservative Party counsel Arthur Hamilton of fabricating evidence. The Crown said Sona believes that witnesses provided erroneous statements against him in order to secure promotions and that the Crown has withheld evidence — a suggestion the Public Prosecution Service of Canada denies.

During a November publication ban hearing in Ottawa, Mathews acknowledged that Hamilton had attended witness interviews with Elections Canada investigators.

Documents obtained by HuffPost show Hamilton prompted and coached several witnesses, including Rebecca Docksteader, during their interviews:

MR. HAMILTON: Can I just interject for a one minute? You'd also mentioned to me a piece of information about this burner phone. MS. DOCKSTEADER: M'hm. MR. HAMILTON: And the covering of his tracks. MS. DOCKSTEADER: Right.

In court, Mathews said Hamilton showed up with all but one of the witnesses, that he arranged the timing of the interviews and that he even called the party lawyer to help persuade a reluctant witness, Tyler Barker, to sit down for an interview. Barker is a staffer for Conservative Senator Carolyn Stewart Olsen.

Mathews also said Hamilton "produced" three junior staffers employed by Conservative Parliamentarians to testify against Sona: Docksteader, John Schudlo and Mitchell Messom.

"He phoned me and told me that he had individuals he believed relevant to my investigation, which he thought I should interview," Mathews said, in telling the court on Nov. 13 about his conversation with Hamilton.

"Docksteader, Schudlo and Messom were strangers to me, and I had no reason to anticipate what evidence they could provide or not provide," the Elections Canada investigator said.

At one point in Docksteader's interview with Elections Canada, Hamilton helps her remember the office location of MP Eve Adams, Sona's former boss. Another investigator, Ron Lamothe, interjects to say he suspects the witness has been told what to say.

INVESTIGATOR LAMOTHE: I'm going to use the term, "coached," you know. MS. DOCKSTEADER: Yeah. INVESTIGATOR LAMOTHE: You discussed this with a number of people, okay? Were you coached? How did they approach you with regards to what you should say? MS. DOCKSTEADER: Today? INVESTIGATOR LAMOTHE: Yes. MS. DOCKSTEADER: I don't feel like I was coached in any way with specifics. I was told that, you know, I would be — you know, that the information that I had could be helpful in the investigation and so that I would be here to present that and that would be — that was it.

Mathews told the court that he never asked the witnesses if they were concerned that Hamilton was monitoring what they were saying. None of the witnesses told him they didn't want him there, Mathews said.

"No, had that happened, I would have stopped the interviews immediately," he told the court.

Transcript excerpts obtained by HuffPost and Global News suggest Hamilton also led the questioning of Conrad Johnson, a former staffer.

Prime Minister Stephen Harper's former chief of staff, lawyer Guy Giorno, offered to accompany Johnson to the Elections Canada meeting, but Hamilton told him he would take care of it.

"It's like, 'Guy, I can't tell you why, but I'm a veteran on this, so I’ll take Mr. Johnson over if that helps,'" Hamilton told investigators.

Hamilton did not return calls and emails seeking comment.

All six witnesses who came forward and told investigators of conversations they had with Sona were Conservative Party staffers. Two worked for MP Chris Warkentin, two for Stewart Olsen and another for the late senator Doug Finley. Another, who provided only a written statement, worked in the Prime Minister's Office.

Conservative spokesman Cory Hann told HuffPost that the party "proactively reached out to Elections Canada and provided any documents or records that may assist their investigators."

But the head of Elections Canada noted in a Commons committee hearing that it took the Conservative Party's lawyer three months to respond to robocall inquiries from the agency after the May 2, 2011 election.

Docksteader told investigators that when she heard about the robocall investigation in February 2012, she reported a conversation she had had with Sona to her boss, Warkentin.

He then spoke to Jenni Byrne, who was the Conservative Party's campaign manager during the 2011 election. After the election, Byrne became the party's director of political operations and was promoted last year to become Harper's co-deputy chief of staff.

In court, it was unclear whether it was Byrne or Fred DeLorey, the party's communications director, who contacted Hamilton.

Prescott said Byrne asked him on Nov. 30, 2011, to delay speaking to Elections Canada investigators until she could get legal advice, according to Postmedia News.

Mathews told the court he had great difficulty getting Prescott, a "very relevant individual" from the Conservatives' Guelph campaign, to speak with him. Prescott waited nearly two months before speaking to investigators, with Hamilton present. He then obtained his own counsel and refused to be interviewed.

The physical evidence in the case suggests that Prescott's computer was used to access the illegal robocalls account. Prescott also had an account with RackNine, the company used to place the illegal calls. He said he used RackNine to place legitimate calls to Guelph voters during the campaign. But Prescott and campaign manager Ken Morgan failed to disclose the cost of those calls, which in effect hid the Burke campaign's connection with RackNine from Elections Canada.

Morgan, who was ultimately responsible for the Burke campaign, refused to co-operate without providing any reason, investigators say. He moved to Kuwait a few months after the election.

Trent Blanchette, another campaign staffer, also refused to talk to Elections Canada. Mathews described Blanchette as directly involved with the database's access and use.

WAS SONA IN ARUBA AT THE TIME OF HIS ALLEGED CONFESSION?

Docksteader and Schudlo told investigators that Sona visited their office after the election, boasting about orchestrating calls to trick Liberal voters into believing their polling station had changed. They described how he had bought a disposable phone and called in a favour with a friend to get a list of Liberal supporters.

Messom also said Sona bragged about the robocalls after the election.

Some of the information the three witnesses discussed was already reported in the media, such as the burner phone and the use of a prepaid Visa card.

Many of the new details the witnesses provided to investigators were later proven incorrect.

The list of voters almost certainly came from the Conservatives' database, despite Docksteader's and Schudlo's reporting that Sona had suggested it came from a Liberal source. A federal court judge pointed the finger at the Conservatives' CIMS (Constituency Information Management System) database. Christopher Rougier, the party's director of voter contact who oversees CIMS, also told investigators he believes the list was used to make the fraudulent robocalls.

Docksteader and Schudlo said Sona told them he sent voters to a fake polling station in Guelph's Old Quebec Street Mall, which they described as "old" and "rundown." The mall is in fact a multimillion-dollar project that opened in 2002.

Messom told investigators Sona said he bought a prepaid credit card from a gas station, but in fact the card was purchased from a Shoppers Drug Mart.

Schudlo and Docksteader said that Sona told them about the robocalls when he visited their office "about a week to 10 days" after the election, which would have been between May 9 and May 12.

Information obtained by The Guelph Mercury and iPolitics suggests, however, that Sona was actually in Aruba during that period.

Guelph writer Scott Tracey said Sona shared a reservation notice showing that he flew from Ottawa to Aruba on May 7 and returned a week later, on May 14.

However, other witnesses told investigators that Sona spoke to them about the scheme in conversations before and after the Aruba dates.

Docksteader and Schudlo said Sona may have been working with one other person but that the robocalls were not a widespread operation.

Docksteader described Sona's motivation as a "juvenile competition" between the campaign staff of the Liberal Party and the Conservatives, saying that this was Sona's way of "one-upping" the Liberal opponents.

Last spring, a federal judge ruled that fraud had occurred during the 2011 election. Justice Richard G. Mosley was not asked to rule on the misleading calls in Guelph but rather on the impacts of robocalls in six other races. He said the fraud was widespread but thinly scattered, and said the Conservative Party's database was likely the source of the robocalls. He made no findings that the party was directly involved in the campaign to mislead voters but did chastise Conservative MPs for trying "to block these proceedings by any means."

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