The first time this affair was mentioned, it was in an Agence France-Presse article published on page 1 of the Montreal newspaper La Presse. It was the only paper in Canada that picked it up at the time. It wasn't about Mr. Mulroney; it was about an investigation conducted by Canadian police authorities and that involved money that had purportedly been paid in kickbacks to Canadian politicians. That was the first leak. It was on November 12, 1995. That came from the Agence France-Presse, from Geneva or Zurich; you'd have to check it.
On February 7th, 2008. See this statement in context.