Jean Ann James was suspected in the murder of Gladys Wakabayashi, who was discovered with her throat slit in her Vancouver home in June 1992.
An investigation at the time didn't find enough evidence against James, so police launched an undercover operation in 2007 to set up a fake criminal organization and she confessed to a supposed crime boss in a so-called Mr. Big operation.
James was convicted of first-degree murder in November 2011 but filed an appeal, claiming the trial judge made several errors.
She said the judge should not have allowed opinion evidence from police about a partial shoe print found at the crime scene, and did not properly instruct the jury on evidence of bad character she offered to the undercover officers.
The appeal court rejected the appeal, upholding the judge's conduct, saying the only mistake he made was a harmless one and the evidence against James was overwhelming.