His legal team is arguing that there was no definitive proof of her death, as her body has never been recovered. This lack of physical evidence is central to Miller's appeal against his 2019 conviction.

During the original trial, the prosecution's case was built on circumstantial evidence, including mobile cell site analysis showing that Murray's phone remained with Miller after her disappearance, and text messages he sent from her phone to create the illusion that she was still alive. Despite these factors, Miller maintained that Murray left him to start a new life and denied any involvement in her death.

Miller's barrister, Desmond Hutton KC, argued that there could be other explanations for Murray's disappearance, including potential sightings of her after 2012 and the possibility that she may have met with foul play at the hands of someone else.

The prosecution's case was that Miller killed Murray at their home in County Tyrone, but without her body, the defense contends that there is reasonable doubt regarding her death and Miller's role in it.

Miller was found guilty and sentenced to a minimum of 16 years in prison. Since the conviction, police have conducted searches, including draining a quarry near Benburb, but have not found Murray's body. They have also urged Miller to reveal the location of her remains, which he has not done.