In 2012, Duffy was accused by the media and Senate of improperly claiming primary residency outside of Ottawa in order to claim living expenses for time working in Ottawa. Three other senators, with different fact cases, were also accused of filing false expenses. On February 28, 2013, the Senate Committee on the Internal Economy announced that Duffy, Pamela Wallin, Mac Harb, and Patrick Brazeau would be subject to a forensic audit to determine appropriateness of their expense claims. After several weeks of negative publicity, Duffy, despite believing he was entitled to claim the PEI residence, volunteered to pay back the expenses he had claimed for his Ottawa residence. Prime Minister Harper's Chief of Staff, Nigel Wright wrote a personal cheque to Duffy for $90,172 to cover past residency expenses claimed as part of an agreement Duffy made with the Prime Minister's Office. Duffy then repaid the Government of Canada $90,172 in March 2013. Duffy resigned from the Conservative caucus on May 16, 2013, and became an independent senator. On November 5, 2013 the Senate voted to suspend Duffy and two other senators. However, in his trial decision exonerating Duffy in 2016, Ontario Superior Court Judge Charles Vaillancourt said Duffy had not falsely claimed living expenses. The judge said Duffy had no choice in the matter, as he had been appointed to represent Prince Edward Island in the Senate.