Conservative MPs are being given assurances by party brass that there is not a high-placed mole within the ranks of the governing Tories after a series of embarrassing leaks of internal documents to the media.

Sources say party executive director Dimitri Soudas gave a brief presentation to the weekly Conservative caucus meeting Wednesday to explain how a number of confidential party documents ended up in the hands of journalists.

Party officials had been peppered with questions in recent days about who was behind the unauthorized release of election strategy plans, internal memos and a draft hiring agreement of a former Prime Minister's Office chief of staff to the Toronto Star.

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MPs and rank-and-file supporters have been wondering if this was a case of negligence or a fifth columnist.

The message to Conservative MPs was that it was neither, sources say.

Mr. Soudas told MPs that it wasn't a staffer responsible, saying instead it was a theft of the information by an outside person.

He didn't go into great detail when talking to Tory caucus.

But people familiar with the matter say the party believes the leaks can be traced to a computer used by party officials during an early February meeting of the Conservative National Council at a downtown Toronto hotel. The computer wasn't owned by the party.

While Tories had erased the data they'd transferred to this computer after using it, sources say that it's believed someone who was not a Conservative supporter got hold of the machine and managed to recover the deleted information.

This outsider appears to have reconstructed the documents that the Conservatives had stored on the computer and then anonymously e-mailed them to the Toronto Star, sources said.

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The leaks, the paper reported, included plans to target Liberal Leader Justin Trudeau at a coming Liberal convention with an orchestrated campaign to disrupt Liberal communications, highlight disunity in his ranks and question his leadership abilities.

They also included a memo marked "secret" to Prime Minister Stephen Harper proposing to take measures to help incumbent MPs secure their party nominations well before the next election. It said 130 sitting MPs indicate they plan to run again, 11 will not, and 16 are "unsure."