TORONTO — For a Canadian prime minister who has tied his legacy to improving the state of Indigenous people in the country, the Valentine’s Day photo would seem a picture-perfect re-election campaign poster: Justin Trudeau’s face cupped in the hands of his justice minister and attorney general, Jody Wilson-Raybould.

Ms. Wilson-Raybould was a powerful regional chief of First Nations on Canada’s west coast, an advocate for Indigenous rights and a lawyer. The photo of her and Mr. Trudeau was confirmation that a new postcolonial Canada was being built.

A year later, Ms. Wilson-Raybould has resigned from Mr. Trudeau’s cabinet, after being moved from the post of justice minister to minister of veteran’s affairs, widely considered less influential. And now Mr. Trudeau is under attack from Indigenous groups, who say her treatment raises questions about his commitment to righting the wrongs of the past.

Ms. Wilson-Raybould’s resignation came a week after a Canadian national newspaper reported, on anonymous sourcing, that either Mr. Trudeau or his staff had pressured her to back off the corruption and bribery prosecution of a prominent, Montreal-based engineering company, SNC-Lavalin.