The RCMP alleges that Sen. Mike Duffy changed his banking address from Ontario to Prince Edward Island shortly after the Senate announced an internal audit of each senator’s primary residence.

New court documents filed Thursday show that the Mounties are seeking documents from Royal Bank and the Canadian Imperial Bank of Commerce for its investigation into the expense claims filed by Duffy.

Cpl. Greg Horton wants credit card statements from CIBC, and credit card and bank account statements from RBC. Horton is also requesting from RBC a mortgage application and, “a list of all address changes in relation to any account solely or jointly in the name of Michael (Mike) Duffy” registered to his Ottawa or P.E.I. homes.

Horton says a report from FINTRAC, Canada’s “finance intelligence unit” that operates independently of the federal government, shows Duffy changed his banking address “from an Ontario address to a P.E.I. address “on December 10, 2012.

“The date coincides with the timing of the December 6, 2012 Senate announcement of an internal audit pertaining to primary and secondary residency of all Senators,” Horton says.

Horton repeats his allegations in previous court filings that he believes Duffy “has committed Breach of Trust in relation to travel and housing expense claims, submitted in relation to his duties as a Canadian senator.”

The RCMP is investigating the expense claims filed by Duffy, as well as Sen. Patrick Brazeau and Sen. Mac Harb. They are reviewing bank, credit card and other financial documents, as well as the external audits conducted of all three senators’ expense claims.

In various court filings, Horton alleges that all three senators have committed breach of trust related to their expense claims.

Earlier this month, Horton filed documents requesting records and billing statements related to Brazeau’s expense claims, as well as all of his cellphone and corporate credit card records dating back to March 2011, when he is alleged to have begun making improper housing claims.

Horton alleges that Brazeau does not live in the Manawaki, Que., home he claimed as his primary residence.

Senators are eligible for an annual housing allowance of up to $22,000 if their primary residence is more than 100 km from Parliament Hill.

In separate court filings, Horton alleges Harb set up an elaborate scheme to cheat taxpayers of hundreds of thousands of dollars in fraudulent housing and living expenses claimed on an “uninhabitable” home.

The Mounties have requested records and billing statements from the Senate related to his expense claims, as well as his cellphone and corporate credit card records from the Senate dating back to Sept. 2003, when he was appointed to the Upper Chamber.

Duffy repaid some $90,000 in expenses with help from Prime Minister Stephen Harper’s former chief of staff, Nigel Wright, before the results of his external audit were released. That deal is also under investigation by the RCMP.

Brazeau was ordered to repay about $49,000 in ineligible housing and travel claims, but missed his first payment deadline and his salary is now being docked.

Harb repaid $51,000 in improperly claimed expenses, but is fighting the Senate’s repayment order in court. Sen. David Tkachuk, who served as chair of the Senate’s Internal Economy Committee, alleged in June that Harb in fact owes more than $230,000.