The Conservative Party is reviewing tapes of every call made by the Responsive Marketing Group call centre in Thunder Bay, Ont., in the last election before Elections Canada investigators arrive next week, CBC News has learned.

Investigators are planning to interview the centre's staff, which the Conservative Party hired to make phone calls to identify and rally supporters in the 2011 federal election.

Conservative Party spokesman Fred Delorey denied that Conservative officials are reviewing the tapes.

"The Conservative Party is not reviewing tapes from the last election," he said in an email to CBC News.

And election commissioner William Corbett has assigned veteran investigator Ronald Lamothe, who was the lead on the in-and-out probe into 2006 election spending, to head inquiries in Thunder Bay, the Toronto Star reported.

The commissioner of Canada elections ensures compliance with election laws.

On Thursday, Conservative MPs' counterattack backfired after they accused the Liberals of being behind mysterious election calls — but mixed up two similarly named call companies, naming the wrong one as the smoking gun.

After a week of denials over the role the Conservative Party and a campaign team played in phone calls directing voters to the wrong polling station, and opposition party allegations over harassing calls in other ridings, Prime Minister Stephen Harper pushed back in question period.

The Liberals, Harper said in the House, have said people got misleading phone calls from numbers in the United States. But when two of his MPs tried to offer more details, they named a U.S.-based company that the Liberals have never used.

Prime Minister Stephen Harper and the Conservatives hit back against opposition claims over misleading phone calls in the last federal election during question period in the Commons on Thursday. (Adrian Wyld/Canadian Press)

Interim Liberal Leader Bob Rae said Harper was smearing thousands of Canadians complaining about the calls.

"The prime minister and his colleagues have remarkable ability to turn themselves into victims," Rae said.

"The prime minister cannot deny the fact that two of the companies that are involved with respect to [campaign] activities are now under serious investigation. Nor can he deny the fact that there is an RCMP investigation ongoing with respect to what happened in Guelph."

Elections Canada is investigating automated robocalls in Guelph, Ont., that tried to send voters to the wrong polling station on election day.

Opposition MPs say they have reports of robocalls or strange, harassing live calls from more than 45 ridings in the lead-up to the May 2, 2011, election. They allege the Conservative campaigns made the rude calls, claiming to be the Liberals, in an attempt to make the Liberal campaigns look bad. Harper says the opposition parties didn't report the calls at the time and are acting like sore losers.

Conservatives mix-up companies

But the counterattack backfired when Conservative MPs mixed up two companies with the same name.

Pierre Poilievre and Dean Del Mastro pointed in question period to Liberal candidates who, they said, used a company based in North Dakota to make calls soliciting support.

"The opposition parties said that [their supporters] received calls from a telephone firm with offices in North Dakota. But the only party who hired a firm with offices in North Dakota was the Liberal Party," Poilievre said.

NDP MP Charlie Angus, who spoke right after Poilievre, pointed out that was incorrect.

"Mr. Speaker, they're going to need to get some better researchers, because there is a firm in North Dakota with the same name, but it actually doesn't work for the Liberal Party," he said.

The confusion centred on three call companies with similar names, including Prime Contact Group, based in Canada, and Prime Contact Inc., based in North Dakota.

A spokesman for Prime Contact Inc. told CBC News that the company has never worked for a Canadian political party or candidate and is not affiliated in any way with Prime Contact Group.

Harper said a third company, First Contact, routed its calls through the U.S. A number of Liberal campaigns used First Contact for calls during the 2011 election and in at least one previous election.

But First Contact owner Mike O'Neill told the CBC's Dave Seglins last April that someone was "spoofing" First Contact's numbers — projecting a fake caller ID — to impersonate his company.

Bogus caller IDs and phone numbers

CBC News conducted its own experiment and found dozens of online companies and services that allow users to create bogus caller IDs and faked display phone numbers. It takes just seconds and can be done for just pennies per call.

A spokesman for Harper says First Contact's servers are in the U.S., so the phone number will appear as a U.S. number.

But O'Neill told Evan Solomon, host of the CBC's Power & Politics, on Thursday afternoon that First Contact does not route calls through the U.S.

"All of our live calls are made from centres in Canada under our direct supervision. All of our data and servers are hosted in Canada. We have never engaged a U.S.-based call centre and we have no links to any businesses operating in North Dakota," O'Neill wrote in an email.

First Contact provided services to more than 80 Liberal candidates in the 2011 election, O'Neill said.

He explained that when companies like his and political parties want to conduct telephone town halls, they are limited "to a handful of telephone town hall providers and their proprietary technology, and all are U.S.-based." The hosts, program moderators and guests are still located in Canada, O'Neill said.

Liberal MP Frank Valeriote, the MP for Guelph, said on Power & Politics while on a panel with Del Mastro that, "it is ridiculous to think that Liberals would try and suppress their own voters from coming out to vote."

"That is just absurd," he said, adding that he thinks it shows the Conservatives are desperate to deflect the accusations.

NDP MP Pat Martin, following question period, said the Conservatives are trying to "muddy the waters" by saying that the Liberals made harassing phone calls to their own supporters.

He also put forward a theory about why Conservatives would allegedly try to suppress the vote in ridings where they were headed for clear victories.

"I'm telling you why, because they're trying to starve their political opponents for resources. Every vote that they divert from the polling station for our party is $2 less per year over four years," he said, referring to the per-vote subsidy that parties receive.

Elections Canada not reporting on investigations

Earlier in the day, a democracy watchdog group urged MPs to demand more from Elections Canada when it comes to reporting on how the agency follows up on complaints.

A spokesman for Democracy Watch says 2,300 complaints were submitted to Elections Canada between 2004 and 2011, but the agency didn't report on whether it investigated or what it found.

"Our MPs have kind of dropped the ball here because what they should have been doing is asking for this information, not only from Elections Canada but from every single watchdog," Tyler Sommers said.

Elections Canada has refused to confirm its investigation in Guelph, although the RCMP has confirmed it is assisting in the investigation.

"It’s likely that the robocall issue is only the tip of the iceberg and that, because Elections Canada hasn’t been disclosing information like they should, there are going to be some serious questions about whether our elections have been fair since 2004," Sommers said.

He said reports of automated calls directing voters to the wrong polling station in Guelph, Ont., in the last federal election are "very disturbing."

Sommers said Democracy Watch will push MPs to demand information about any investigations Elections Canada leads.

"It's very simple. Elections are the cornerstone of any democracy," he said. "Without faith in elections, you can’t have faith in the rest of our democratic institutions."