Federal ethics commissioner Bernard Shapiro is stepping down from his high-level post, although it's not immediately clear why.
A spokesperson gave no reason Thursday for Shapiro's decision to resign.
The move comes a year after Prime Minister Stephen Harper refused to co-operate with an investigation by Shapiro into whether ethics rules were broken when Harper wooed Liberal David Emerson to join the Conservatives and become minister of international trade.
Shapiro concluded in the end that no rules were broken.
Shapiro also rejected a request to investigate former prime minister Paul Martin's role in persuading Belinda Stronach to cross the floor and join the Liberal ranks.
Shapiro also cleared Martin's staff in the so-called Grewal affair. Then-Tory MP Gurmant Grewal had accused Martin's staff of trying to induce him to support them in a confidence vote.
Shapiro dismissed his complaint and chided Grewal, who secretly taped the negotiations, for his behaviour.
Shapiro, 71, became the country's first ethics commissioner when Martin created the position in May 2004.
He oversaw the code of conduct for members of the House of Commons and ethical guidelines for cabinet ministers and other public office holders.
Shapiro was also a former president of McGill University in Montreal.
