Justin Stein: Drowsy-causing drug found in slain Charlise's system

Schoolgirl Charlise Mutten had traces of an anti-psychotic drug in her system when she died and her alleged killer had a prescription for the same drowsiness-causing medication, a jury has heard.

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.

Charlise’s body was found dumped in a barrel by the Colo River, northwest of Sydney, four days after she was reported missing by her mother Kallista Mutten.

The schoolgirl had been staying at a nearby property with Stein and Ms Mutten at Mount Wilson at the time of her disappearance.

Forensic testing of Charlise’s remains showed the presence of anti-psychotic drug, quetiapine, for which Stein had a prescription to treat his schizophrenia.

The most common side effects of a child ingesting quetiapine were sedation or drowsiness, the trial was told on Thursday.

Toxicologist Judith Perl said based on the available evidence it was possible - but not conclusive - to say the drug had been ingested within six hours of the girl’s death.

“It is impossible to estimate a dose or time when the quetiapine was ingested,” she told the court.

Dr Perl also said it would be highly unlikely a nine-year-old would be prescribed the drug and that an adult dose ingested by a child would likely cause “significant sedation and vomiting”.

“It’s a drug which can produce central nervous system suppress,” she said.

“It alters the level of alertness in a person.”

Stein told police that Charlise had been sick and vomiting when she woke up on the morning of January 12 and that he gave her two Nurofen-brand ibuprofen tablets.

But Dr Perl told the court there were no traces of ibuprofen present in toxicology samples taken from Charlise.

The jury also heard on Thursday that an “agitated” Stein denied any involvement in the schoolgirl’s disappearance to neighbours as search parties scoured surrounding bushland.

A resident of a neighbouring property, Jane Hutt, told the court she met Charlise on January 3 when she went for dinner with Stein, Ms Mutten and the girl.

Ms Hutt described Charlise as being “very loving and affectionate” with her mother.

“I think they were cuddling ... she was affectionate with us too,” she said.

“She seemed really chatty and comfortable with adults.”

When the search for the missing girl entered its third day, Ms Hutt initiated a conversation with Stein in which she asked if he knew where the nine-year-old was, the court heard.

“He got up and started to get very agitated and straight away he goes ‘Kallista has done something with the girl’,” Ms Hutt said.

“I said something along the lines of, ‘well where do you think, what do you think Kallista has done?’.”

Stein allegedly told her that Ms Mutten wanted to keep Charlise and not return her to her grandparents, adding that the girl was taken by one of her mother’s associates.

“She didn’t want to give the girl back,” Stein said, according to Ms Hutt.

“She wanted the three of us to run away,” he allegedly added.

“That would be the easiest way for me to go back to jail.”

Stein was tracked driving to several locations across Sydney after Charlise’s disappearance, allegedly with the barrel containing her remains on the back of his ute.

Ms Hutt said she noticed nothing unusual happening in the area in the days before the girl’s disappearance was reported to police by Ms Mutten on January 14.

The trial continues.