The federal New Democrats have asked the Mounties to determine whether Prime Minister Stephen Harper's former right-hand man broke any laws by cutting a personal cheque to cover an embattled senator's improper housing expenses.
The NDP's ethics critic, MP Charlie Angus, wrote to RCMP Commissioner Bob Paulson on Monday asking the force to look into the actions of Nigel Wright.
Wright abruptly quit his job Sunday as Harper's chief of staff, days after it emerged that he gave Sen. Mike Duffy $90,000 to repay his housing claims.
Angus says the gift may have broken the law. He added that Harper had a duty to explain to Canadians just what happened.
"We haven't heard the prime minister say that a secret cash payment to a politician is wrong, and whether the prime minister knew, at what point he knew. He must have known something," Angus said.
"Because if it happened under his watch and he did nothing about it, that would be absolutely shocking."
Harper is expected to address the Conservative caucus Tuesday morning before departing to South America for trade talks.
Wright's resignation followed that of Duffy, who left caucus on Thursday facing a potentially humiliating showdown with his Senate colleagues. Colleague Pamela Wallin, who is facing her own expenses audit, also stepped down on Friday.
The ethics commissioner is also looking into Wright's repayment of Duffy's expenses.
At least one Tory MP was trying to put a decidedly optimistic face on a week that saw Harper lose two Conservative senators and his top aide.
Conservative MP Joan Crockett took to Twitter on Monday to trump her party's commitment to ethics.
"Our govt has the highest ethical standards demonstrated by 3 resignations: 2 from Senate caucus & the PM chief of staff," Crockett wrote.
"Those whose actions don't stand up to scrutiny, resign. Unlike the opposition. It's a clear demo of accountability folks from some other parties could emulate. #liberals"