Denis Florien Ratte told undercover police officers posing as gangsters that he had killed his wife, who disappeared from Prince George, B.C., in 1997.
Police mounted the sting in 2007 and got Ratte to tell them details about the killing.
After his arrest, Ratte confessed, but recanted at trial.
He was found guilty of second-degree murder and the British Columbia Court of Appeal dismissed his appeal.
The Supreme Court, as usual, gave no reasons for refusing to hear the case.