A former Conservative staffer under investigation by the RCMP has left his volunteer job in a key electoral battleground, Prime Minister Stephen Harper says.

Harper told a news conference in Regina on Tuesday that Sebastien Togneri is no longer working in the riding of Edmonton-Strathcona.

"My understanding is that he volunteered for a campaign," Harper said. "My understanding is that he is no longer a volunteer for that campaign. And that's all I know."

The announcement came after The Canadian Press learned Togneri was helping with the campaign of Ryan Hastman, a popular Conservative with ties up to the Prime Minister's Office.

Hastman is trying to wrest away the only riding in Alberta the Conservatives did not win in 2008.

"Sebastien was in Edmonton and volunteered to put some signs together. He is no longer volunteering on the campaign," said Paul Bunner, a spokesman for Hastman.

As a senior aide to a cabinet minister in 2009, Togneri demanded that government officials block the release of a document requested by The Canadian Press under Access to Information laws.

Public Works Minister Rona Ambrose called in the Mounties this month to determine if charges should be laid after Canada's information commissioner found Togneri clearly interfered with the request without legal authority to do so.

Togneri resigned from the government after he was encouraged to do so, but he is apparently not keeping his distance from Ambrose or Harper. Multiple sources said Togneri turned up at Harper's rally near Edmonton on Monday evening.

Hastman was featured during the well-attended event, appearing in a photo opportunity with his family and Harper. He is a former aide to the prime minister and previously worked for Stockwell Day.

Hastman's campaign manager, Julian Martin, confirmed that Togneri had "come on by" to work on Hastman's campaign, noting that the two men were friends. He bristled at a question about whether Togneri was providing strategic advice to Hastman.

"Oh come on, no, he's putting out signs," said Martin.

Togneri resigned from the office of Natural Resources Minister Christian Paradis last fall. The government's encouragement of the resignation and the call to the RCMP was held up as evidence that the government was taking the allegations seriously.

"Let me be clear, no current member of this government is involved in this case,' Ambrose said on March 14. "Our government expects all public servants and political aides to abide by the Access to Information Act."

Ambrose, who was also at Harper's event on Monday, said she was not aware that Togneri was working in the nearby riding.

Liberal Leader Michael Ignatieff says he's troubled by Togneri appearing to work for Hastman in the riding.

"This man is accused of fooling around with our democracy," he said, adding it's a citizen's right to have access to information from the government.

"I think the voters of Edmonton-Strathcona would be interested to know what he's doing there," Ignatieff said.

The RCMP say they are are evaluating the evidence and have not decided whether or not to launch an investigation.

Bloc Leader Gilles Duceppe says it shows what the Conservative Party really thinks of what Togneri did, despite the fact he resigned.

Meanwhile, NDP Leader Jack Layton said the Conservatives are throwing Togneri under the bus. Layton also asked when Harper would do something about two Conservative senators charged with election fraud.

Hastman replaced Rahim Jaffer as the candidate in Edmonton-Strathcona last 2009 and has been campaigning ever since.

Togneri's meddling in Access to Information came to light when documents revealed he had tried to stop the release of Public Works records to Canadian Press reporter Dean Beeby in 2009.

The issue was brought before a Commons committee last year, where Togneri said he had made a mistake and that the interference was an isolated incident. The Canadian Press subsequently reported that Togneri appeared to have meddled in at least three other cases. Togneri submitted his resignation after those revelations.

Information Commissioner Suzanne Legault found evidence of interference in Togneri's case, and is still investigating three departments over similar concerns. The commissioner does not have the power to lay charges under the Access to Information Act. She has to call in the RCMP to take that kind of action.

Being found guilty of breaking access laws can carry a maximum penalty of two years in prison or a fine of $2,000.

Legault's findings and Ambrose's announcement of RCMP involvement became part of the narrative the opposition parties used to argue the Conservative party was not to be trusted with Canadian democratic institutions and had been flouting principles of transparency and accountability.

The same week that Ambrose called in the Mounties on Togneri, the Prime Minister's Office asked the force to investigate allegations of influence peddling by former Harper aide Bruce Carson.

with files from CBC News