Schoolgirl was drugged and shot dead by her stepdad, jury told - as alleged killer's claims that she was murdered by her own mother are dismissed as 'nonsense'

Prosecutors have urged a jury to find that Charlise Mutten was drugged and fatally shot by Justin Stein, describing his version of what happened to the schoolgirl as 'nonsense'.

Stein, 33, has pleaded not guilty to murdering the nine-year-old in January 2022, claiming it was the girl's mother, Kallista Mutten, who shot her.

Charlise's body was found dumped by the Colo River, northwest of Sydney, four days after she was reported missing, with gunshot wounds to her head and lower back.

Crown prosecutor Ken McKay SC told a jury during his closing address on Wednesday that prosecutors did not have to prove a motive.

He invited them, however, to find Stein shot and killed Charlise because he was concerned about being found to have given her anti-psychotic drugs.

Toxicology results revealed Charlise had traces of the drug Seroquel, for which Stein had a prescription to treat schizophrenia, in her system.

An adult dose of the drug would have a profound sedating effect on a child, the court was previously told.

Charlise had been visiting her mother and Stein, who were in a relationship at the time, over Christmas.

The group spent their time between a Mount Wilson property owned by Stein's mother and a caravan at the Riviera Ski Park, about a 90-minute drive away.

Prosecutors allege Charlise spent the night alone with Stein at the Mount Wilson property on January 11 and he killed her either that evening or the next day.

To convict Stein, the jury must be satisfied there was no reasonable possibility that Ms Mutten shot her own daughter, Mr McKay said.

During his evidence on Monday, Stein agreed he spent the night of January 11 at the property with Charlise but said the girl was alive the next day.

According to Stein, Charlise travelled with him to pick Ms Mutten up from the caravan before all three went to Sydney.

He said they returned together to Mount Wilson in the evening.

Phone records show Stein called his mother at 8.59pm on January 12 and spoke to her for several minutes, which both Stein and his mother agree occurred.

It is also not in dispute that Ms Mutten searched for hospitals in the area on her phone about 9.21pm and later placed calls to Lithgow Hospital and Blue Mountains Hospital.

In the short period between those two events, Stein said Ms Mutten shot her daughter and moved the body.

He said that after speaking to his mother he checked on Charlise before doing some work on a car in a shed on the property.

By Stein's account, he then heard a gunshot and left the shed to see Ms Mutten shooting her daughter for a second time.

Stein said Ms Mutten demanded he get a tarp from the shed, which he claimed took him up to 10 minutes.

When he returned, both Ms Mutten and Charlise were gone, he said.

'It's just a nonsense that version,' Mr McKay told the jury.

'Matter for you, but it just did not happen that way.'

Mr McKay said Ms Mutten calling local hospitals was consistent with the belief that her daughter was missing and not with the woman having just shot her.

'If you were thinking, 'oh, better get her some medical assistance', you'd ring triple zero,' he said.

'But ringing a hospital, a kids' hospital, you're looking to see if someone's there.'

During cross-examination on Tuesday, Mr McKay put to Stein he had murdered Charlise after giving her Seroquel.

Stein denied the claim, saying: 'I never touched her.'

The trial continues.