OTTAWA - A Conservative staffer who blocked the release of a report to the media repeatedly evaded questions on how many other times he interfered in the Access to Information system.

Sebastien Togneri had previously told a House of Commons committee that he made a "mistake" in ordering that a 137-page document -- already cleared by non-partisan civil servants and government lawyers -- be "unreleased."

Under further questioning before the committee on Tuesday, the senior aide to Natural Resources Minister Christian Paradis repeatedly consulted his lawyer when asked how frequently this type of practice occurred.

"Uh, in my, my . . . yes it's the only time I, uh . . . This was, you know, a mistake I made," Togneri said.

Asked again for a "yes or no" response, Togneri conferred with his lawyer before eventually responding, "In my mind, yes, it's the only time I intervened but I . . . ."

He hadn't finished his thought before Liberal MP Frank Valeriote asked him if he'd ever suggested to any ATIP officers that they'd wrongly applied the access law.

"I don't recollect. I don't know. I don't think so," Togneri said in quick succession.

And has he ever urged officials to withhold documents, or censor them more heavily?

"I don't recall, no, I don't think so. Either way, I didn't have delegated authority to do so," he responded.

Togneri was working for Paradis at the Public Works Department last summer when he sent a brusque email to civil servants ordering them to "unrelease" an internal report that had been approved for delivery to The Canadian Press. The document, which detailed the government's massive real estate portfolio, was intercepted in the mailroom and was released much later with 107 of its 137 pages blacked out.

The Canadian Press later obtained emails exposing the political interference and the federal information commissioner opened an investigation.

Togneri told the committee he reviewed access requests under direction from the Issues Management branch at the Prime Minister's Office, but purely for communications purposes.

"They never asked us to withhold information or to stop information."

Togneri subsequently told NDP MP Bill Siksay that his "mistake" was in misinterpreting the Access to Information Act as it applied to the content of The Canadian Press request.

"But you've told us you had no responsibility for reviewing the content of documents, only to prepare the minister for a response to what was released," said Siksay.

"That was my mistake," responded Togneri.

The constant contradictions and evasions in Togneri's testimony prompted frustration among MPs.

Asked five times in a row about what happened to the Public Works document after he had it intercepted, Togneri ragged the puck before finally conferring with his lawyer and responding: "I don't know."

"So you never received any directive to intercept the document, but you do intercept it, it comes back to the minister's office and is cut down to 30 pages from over 100 -- and you have no idea what happened?" Bloc Quebecois MP Carole Freeman asked incredulously.

Togneri's testimony under oath came to a mercifully premature end when the fire alarm went off in the Parliament buildings. That prompted Conservative MP Pierre Poilievre -- the parliamentary secretary to Prime Minister Stephen Harper -- to throw up his hands and joke: "I was here the whole time!"

The fire alarm delay also postponed the scheduled testimony of Dimitri Soudas, Harper's director of communications.