In December 2021, nine-year-old Charlise Mutten flew from the Gold Coast to Sydney to spend a month with her mother over the Christmas break.
On the day she was due to fly home police uncovered her body which had been dumped in a barrel, with gunshots to her head and back, near the Colo River in the Blue Mountains west of Sydney.
Her mother's fiance, Justin Stein, 33, pleaded not guilty to killing the schoolgirl at the start of an estimated six-week murder trial on Monday.
At the heart of the trial is Stein's claim that it was not him who killed Charlise, but her mother Kallista Mutten.
Stein does admit helping dispose of the girl's body, according to his lawyer Carolyn Davenport SC, helping explain why he was caught on camera towing a boat with his ute and allegedly the barrel containing Charlise's body on the back.
Ms Mutten met Stein through a prison program while both were serving jail time, the jury heard this week, with the couple continuing their relationship once released.
A long-time ice user, Ms Mutten conceded legal custody of her daughter to the girl's grandparents, after being sentenced to three years' jail for a driving incident in which her passenger was killed.
Stein was jailed for five years over a failed cocaine importation attempt and at the time of Charlise's death was undergoing treatment for heroin addiction.
Ms Mutten and Stein were caught on camera in August 2021, breaking into a house in the Blue Mountains, during which they allegedly stole two rifles - a BSA .22 calibre bolt action and Winchester .30 calibre lever action - one of which prosecutor Ken McKay SC said is central to the crown case.
Charlise had lived with her grandparents at Tweed Heads, on the NSW-Queensland border, from about the age of four, after it became apparent Ms Mutten was unable to properly care for her, with the court being told she struggled with drug-related mental health issues.
Charlise's grandfather, Clinton Mutten, gave stoic evidence as the trial's first witness, remembering the nine-year-old as an unusually bright and well-behaved youngster, who loved animals and dreamt of becoming a veterinarian.
During Charlise's Christmas visit, she, Stein and Ms Mutten spent their time between a property at Mount Wilson, which was owned by Stein's mother, and a caravan at Riviera Ski Park roughly 90 minutes away.
The trip may have initially been a happy one, with photos from Christmas Day sent by Ms Mutten showing a healthy and beaming Charlise who by all accounts was pleased to be there.
Two weeks later, on the morning of January 14, Ms Mutten called police reporting her daughter missing.
Prosecutors are largely relying on mobile phone data including text messages and location records to shed light on what happened to the schoolgirl, by tracking the movements of Stein and Ms Mutten in the days leading up to her death.
The Crown alleges on the evening of January 12, Stein travelled back to the Mount Wilson property alone with Charlise, while Ms Mutten remained at the caravan park.
Police ultimately found Charlise's body by using Google location data stored on Stein's phone, which showed him stop at a remote point on the Colo River where the barrel was found for roughly five minutes in the early hours of January 13.
Before allegedly having dumped the body, the evidence suggests Stein drove to at least three different boat ramps across Sydney, towing the boat with a large item covered by a blue tarp on the back, which prosecutors allege is the barrel containing Charlise.
During the trip, Stein was captured on camera buying five 20 kilogram bags of sand from Bunnings which prosecutors allege he put in the barrel to weigh it down.
Much of the first week of the trial was taken up by evidence from officer in charge of the investigation, Detective Sergeant Bradley Gardiner, during which key exhibits were tendered to the court.
The trial is yet to hear from Ms Mutten who has been flagged as a key witness and prosecutors say may appear in the coming week.
