The Supreme Court of Canada has upheld a lower court ruling that ordered a new trial for a Newfoundland murder suspect.

The justices ruled that so-called Mr. Big stings like the one that convicted Nelson Hart pose major problems — namely, that they tend to produce unreliable confessions and risk becoming abusive.

Mr. Big stings are controversial operations in which undercover officers pose as criminals to draw confessions from suspects.

Hart was convicted in 2007 in Newfoundland of two counts of murder in the drowning deaths of his twin three-year-old daughters.

In 2012, a majority of the Supreme Court of Newfoundland and Labrador's Court of Appeal overturned Hart's conviction, questioning the reliability of his confession to undercover officers posing as members of the mob.

The Crown appealed to the Supreme Court of Canada, which upheld the Appeal Court's ruling and said it is up to the Crown now to decide whether there is enough evidence without the confession to hold a new trial.

More to come