for Senate per diems while on vacation, and while he was working for the Conservative Party during the last election.

Senators Mac Harb and Patrick Brazeau are also the subjects of an RCMP investigation over their expense claims for living expenses in Ottawa. A Senate committee looking into expenses claimed by Pamela Wallin has referred her file to the RCMP as well, though the Mounties have not indicated whether they will investigate.

Each of the senators under scrutiny has said the rules were unclear, or that mistakes were made, or that the rules were followed as they existed at the time of the claims.

Lavigne also said rules were unclear

Former Liberal senator Raymond Lavigne made statements of a similar nature during his trial for breach of trust over false claims hemade about travel to Montreal and for having Senate staff cut down trees on his private property during Senate business hours.

Lavigne, who was a senator from 2002 until he retired after his 2011 conviction, submitted mileage claims for trips to Montreal even though he was travelling in his assistant's car, or sometimes not travelling at all. In court he argued the Senate did not have written rules about claims until 2004, and that the claim forms did not specify that the claimant's own car had to be used.

However the judge ruled, "If he [Lavigne] had any uncertainty, he could have asked the Senate administrative staff if he could claim a reimbursement for travel expenses he did not incur."

At trial, the clerk of the Senate at the time, Paul