An RCMP officer in charge of the investigation into alleged Senate expense wrongdoing has written one of Senator Mike Duffy’s lawyers seeking copies of emails from Prime Minister Stephen Harper’s office that could link senior officials in the PMO to a scheme Sen. Duffy alleges was proposed to cover up a $90,000 payment from the Prime Minister’s former chief of staff Nigel Wright who paid off Sen. Duffy’s Senate expenses last March, a copy of the Mountie letter indicates.