According to the Court of Appeals opinion, the court found that Charles' attorney failed to call several witnesses who might have helped his defense during the 2009 trial.
State prosecutors then petitioned for the Supreme Court to hear the case, but the high court denied the request in 2012. Since then, attorneys have delayed setting a trial until Monday because of issues with forensic evidence, according to court records.
Prosecutors filed charges against Charles in 2007, 11 years after Jamie Ellen Weiss was found dead in a bathtub in her Magna home.
Weiss was 18 when she was found dead on Aug. 7, 1996. While she was found submerged in a bathtub, medical experts said she had no water in her lungs and had, in fact, died from blunt force trauma.
At the 2009 trial, Chief Medical Examiner Todd Grey testified Weiss likely died sometime before Charles went to work at 6 a.m. But Charles told police his girlfriend had helped him start his car that morning, because he could not shift the gears on his car without help if it rested on an incline.
In his appeal, Charles said his defense attorney failed to present evidence that would have corroborated his story that his girlfriend was alive when he left for work.
The appeals court also found the defense failed to put Weiss' cousin, who reportedly saw another car in the woman's driveway on the morning of her death, on its witness list.