Who is leaking Grewal's tape?

CTV's Ottawa Bureau Chief Robert Fife reports two new facts about the Grewal tapes: (1) that Martin knew of the discussion, and (2) that Grewal would get a reward within two weeks of crossing.

On the first point, this is surely not surprising: Martin must have known who was in discussions and what the state of those discussions were. The second is slightly seedier, if a specific price had been agreed on, but again we'll have to wait on the specific tapes.

One point that has not been noticed, however, is nonetheless important. Where did Fife learn of these facts? Surely there are only two possibilities. This came either from the PMO or from the Conservative Party (which now has the tapes). Since this embarasses the PMO, we should probably conclude that it is the Conservatives who have leaked this.

[A further point. It is also being reported (not in the link above) that Fife is saying the tapes might be released today. Since only the Conservatives will know when they will release the tapes, this fact can only come from the Conservatives.]

This, however, is surely intolerable. They have had the tapes for a week and have so far surrendered them neither to the RCMP or to Parliament's ethics commissioner. Only eight minutes of four hours have been released. And now they are surreptiously leaking selected details to the press?