Canada's Prime Minister, Justin Trudeau, is under investigation over a holiday he took on the private island of billionaire philanthropist and spiritual leader Aga Khan.
The federal ethics commissioner must now determine if the visit violated conflict of interest rules.
Mr Trudeau has said he is "more than happy" to answer any questions.
After a preliminary inquiry last week, Ethics Commissioner Mary Dawson said she would formally investigate whether Mr Trudeau had breached ethics laws.
When news of his winter getaway was made public, Mr Trudeau went on the record about the vacation.
He has also admitted to using the private helicopter of the Aga Khan.
At a press conference on Friday, Mr Trudeau said that the stay over the new year was a "personal family vacation".
Mr Trudeau was accompanied on the trip by Liberal MP Seamus O'Reagan and Liberal Party President Anna Gainey, and their respective partners.
Prince Karim Aga Khan is a close family friend of the Trudeaus and was an honourary pallbearer at the funeral of Mr Trudeau's father, Pierre.
The Aga Khan Foundation is a registered as a lobbyist and has received hundreds of millions from the federal government over the past several decades, from both the Liberal and Conservative parties.
Canadian conflict of interest laws prohibit ministers from accepting gifts, including free travel.
No Canadian prime minister has yet been found in breach of a federal statute. But the fallout could hurt Mr Trudeau, who became popular with the voting public because of his accessible style, analysts say.