The federal Liberal Party's public safety critic has written to the RCMP, asking the force to probe the recent run on B.C.'s Taseko Mines Ltd. stock and a possibility the sell-off was triggered by a government leak.

"As the integrity of the federal government and cabinet is a matter of serious public concern, it is in the interest of all Canadians that this matter be resolved," Liberal MP Mark Holland wrote. "I therefore request that you look into this case and determine whether or not there are grounds to launch a formal investigation."

Earlier Thursday, Holland pressed the Tories to reveal whether the RCMP is investigating.

"Someone, somewhere in the Conservative government leaked," said Holland, who led off question period in the House of Commons.

"The government has known this for six weeks. Have they launched an investigation, called in the RCMP?"

Conservative House leader John Baird did not say whether the Mounties would be called in.

Liberal MP Mark Holland, shown in September, asked the Tories to reveal whether the RCMP is investigating a recent run on B.C.'s Taseko Mines Ltd. stock. (Adrian Wyld/Canadian Press) "Here's what we do know: a publicly available environmental assessment on this project stated quite clearly it would cause repairable harm to the environment," Baird said.

"People can speculate what they want. It was significant speculation that the government would approve the project, but we didn't. We did the right thing for our environment."

During his second question, Holland pushed again for an answer on the investigation.

"One day out of nowhere, the stock dropped 40 per cent," Holland said. "That's no accident. This was a decision of the Conservative government, of its cabinet, and when did the share prices plunge? Around the same time the minister secretly met in cabinet to block the mine.

"Normal investors got wiped out, insiders leaked the information and made millions. What assurances do we have the Conservative insiders didn't make out like bandits …?"

Baird responded: "The member opposite sit is engaging in pure speculation. The bottom line is the government did the right thing for our environment."

A big drop

As CBC News first revealed, shares in Taseko Mines Ltd. mysteriously dropped almost 40 per cent in frantic trading on the Toronto Stock Exchange on Oct. 14, more than two weeks before Ottawa announced it was blocking the firm's planned development of a controversial B.C. mine.

Federal officials interviewed by CBC News on condition of anonymity said the unexplained crash of Taseko stock caused instant panic in the ministerial offices that were involved in reviewing the proposed mine. Everyone, they said, had the same fear: that it was a government leak.

There is also pressure coming from B.C. on the issue.

The British Columbia Securities Commission (BCSC) confirmed it is reviewing a referral made to it by the Investment Industry Regulatory Organization of Canada (IIROC) regarding the trading in the shares of Taseko.

The BCSC said in its news release that it does not comment on matters under review.

As well, an MLA from the B.C. Interior is joining calls for an RCMP investigation. Bob Simpson, whose riding includes the proposed Prosperity mine site, calls the possibility of a government leak "deeply troubling."

The proposed mine project, located about 125 kilometres southwest of Williams Lake, has been touted as one of the world's 10 largest undeveloped copper and gold reserves.

The federal government turned thumbs down on the Prosperity Mine on Nov. 2, citing environmental concerns.