Justin Stein, 33, has pleaded not guilty to murdering the nine-year-old in January 2022 as he stands trial in the NSW Supreme Court.

He has claimed it was not him but Charlie’s mother, Kallista Mutten, who shot the girl.

Ms Mutten appeared in the witness box for the first time on Monday as the trial entered its third week.

She told the court that at the time of her daughter’s disappearance she had hopes of marrying Stein and for Charlise to be a part of the wedding party.

Ms Mutten said that on January 12 – on or around the date when police allege Stein murdered Charlise – she believed he might have been organising to elope with her.

The schoolgirl, who lived with her grandparents on the Gold Coast, was visiting her mother and Stein over Christmas at the time of her death.

The group spent their time between a property at Mount Wilson in the Blue Mountains and a caravan at the Riviera Ski Park, about a 90-minute drive away.

Ms Mutten said during the visit Charlise referred to Stein as “dad” or “daddy”.

Charlise was reported missing by her mother on January 14, 2022 and her body was found four days later with gunshot wounds to her head and lower back.

Ms Mutten said Charlise travelled with Stein to the Mount Wilson property on January 11 while she remained at the caravan park.

Stein told her he needed to travel back to Mount Wilson to meet an auctioneer who was due to attend the property the next day to value some items, she said.

Ms Mutten said Charlise had asked her, “Can I go with daddy, mum?”

“I said, ‘yes of course’,” the mother said.

Phone records showed that evening Ms Mutten messaged Stein, “are you ok?” to which he replied that he was cooking chicken and Charlise was playing with some balloons.

Ms Mutten said she woke up feeling sick the next morning, on January 12, and messaged Stein.

“It felt like I ate something not right; I threw up,” she told the court.

“Me and Charlise had some party pies from the day before so I thought maybe that might have been it.”

Stein called Ms Mutten shortly after 9am, according to phone records, during which she recalled him saying Charlise was also not well.

“He did say that youse (sic) must have the same thing because Charlise woke him up early in the morning and that she had vomited on him and on the ground,” she said.

Ms Mutten said she had packed an overnight bag on the understanding that Stein would come that day to pick her up.

“To be honest I thought he was organising us to elope,” she said.

“I wasn’t too sure if that was the surprise that they had for me.”

Ms Mutten said Stein told her that he had left Charlise with the auctioneer due to the girl being sick.

“He did say that she’s got three kids of her own and that she’s practically a nurse, so she’s in safe hands,” she said.

Later that day, the pair drove to Sydney and bought methamphetamine – commonly known as ice – which they both injected at Centennial Park before having sex, Ms Mutten said.

“It gave me energy to be able to function,” she said.

The trial continues.