RCMP are conducting a raid on Conservative party headquarters in Ottawa on Tuesday in connection with an investigation into spending on election advertising.
The Mounties, who have a search warrant, say they are assisting Elections Canada.
Conservative party spokesman Ryan Sparrow had no comment as he entered headquarters.
The issue involves party spending during the campaign for the 2006 parliamentary election.
The party gave $1.2 million to local candidates who hadn't reached their spending limits. That money was then returned to the party, which spent it on regional television and radio ads.
Elections Canada alleges that money drove the party over the $18.3-million spending limit for federal elections.