'I'm not this monster': Mother of murdered nine-year-old Charlise Mutten breaks her silence

At the time of the nine-year-old's death, Kallista was using drugs and her life was out of control.

"I'm not this monster that everyone has read in the papers and the news," she said.

Police cleared Kallista of having anything to do with her daughter's murder early in the investigation, but that didn't stop an angry public.

She was heavily scrutinised and blamed for putting her little girl in harm's way.

But in her first interview, she told 60 Minutes she's a victim, not a villain - manipulated and framed by a man she trusted and even planned to marry.

"I didn't commit any murder or anything like that, but I do take accountability for the things I have done," she said.

In June, Justin Stein was found guilty of murdering Charlise Mutten and sentenced to life in prison without parole.

"Not only did I lose my daughter, I lost a family that I had in my life and a partner that I thought I trusted and knew and it was all completely shattered in one day," Kallista said.

Detective Sergeant Bradley Gardiner, who led the investigation into Charlise's death, said Kallista was an easy scapegoat.

"The community have had their comments about her in terms of being a bad mother," he told reporter Dimity Clancey.

"She also has this burden that she trusted Justin Stein and she regrets that decision every day."

Kallista first met the man who would murder her daughter in 2018.

They were both serving time in jail; Kallista for dangerous driving occasioning death and Stein for importing cocaine.

It was a chance meeting when all inmates, men and women, shared the same visiting area due to renovations.

"We had the same sort of goals where we wanted to do better and have a better life," Kallista said.

"I wish I'd never met him."

After being released from prison, the two continued their relationship and moved into Stein's family home in Mount Wilson, a village in the Blue Mountains two hours west of Sydney.

Charlise stayed in the custody of her grandparents, who had raised her since the age of four.

But despite the distance between them, the bond between Kallista and her daughter remained strong.

"She just was just the most incredible, amazing little girl and every conversation we'd have, I'd always say, 'you're smart, you're kind, you're important' and she'd just lap it up," Kallista said.

But what Charlise really longed for was to be like her classmates and have two parents.

When plans were made for her to spend the summer holidays with Kallista and Justin Stein, Charlise couldn't wait.

Photos taken in the last few weeks of her life show just how fond she was of the man who told her she could call him daddy.

"He actually said in the car, 'I'm always gonna be a father figure to you Charlise and you can call me daddy'," Kallista recalled.

"That was a very touching moment for both of us, because she's always longed for a dad."

At the time of her death, Charlise and her mum had been staying at Stein's caravan park on the Hawkesbury River, a two-hour drive away from the Mount Wilson property.

Charlise had been swimming in the pool at the caravan park, when Stein said he needed to return to Mount Wilson.

What happened next is a moment in time that Kallista replays in her mind every day.

"Charlise said, 'Can I go with daddy, Mum?'" she said.

"'Of course, you can'. Like, I didn't think anything of it. And that's the last time I saw her."

It was the first time in the holiday that Charlise had been alone overnight with Stein.

When he arrived back at Mount Wilson, he sent Kallista text messages to let her know they had arrived safely and Charlise was happy playing.

"I said send my love and make sure she goes to bed on time and brushes her teeth," Kallista said.

"I thought it was just a normal night and they were gonna come back the next day."

Brad Gardiner said no one but Stein knows what happened that fateful night.

But phone records seized during the investigation show he spent hours looking at dating sites and pornography, before shooting the young girl dead in the face.

"There is nothing that a nine-year-old could do to an adult who is there to protect her, that could justify any outcome for what happened," the detective said.

One of the main criticisms Kallista faced was the fact it took two days to report her daughter missing.

But as she told 60 Minutes, she believed a web of lies concocted by Stein to cover his heinous crime.

From a real estate auctioneer to being kidnapped by former criminal associates, Stein spun many stories about who took the little girl.

"It was just all lies, all lies. Everything was lies, but I held on to that hope that she was okay," Kallista said.

But while Stein was able to trick Kallista, he couldn't outsmart homicide detectives who were suspicious of him from the moment Charlise was reported missing.

In the days following the schoolgirl's disappearance, police had to work quickly.

Homicide commander Superintendent Danny Doherty and his team retraced Stein's every move, trawling through hours of CCTV.

"He weaved a web of wicked lies and deception to shift blame from himself on to others, and he wouldn't accept the heinous crime that he had committed," Doherty said.

Stein's phone records would ultimately lead investigators to a location on the banks of the Colo River, where a barrel was found with Charlise's body inside.

Detective Senior Constable Justin Hayton made the gruesome discovery.

"I just had that gut feeling, I just knew it was her. I hadn't seen the barrel before, I just knew," Hayton said.

Within hours, Stein was arrested and charged with murder.

"I just said, 'You're under arrest for the murder of Charlise Mutten'," Gardiner said.

"It's like he was waiting for us to knock on that door."

While police had their man, they still needed to find out how Charlise died.

Detective Hayton stayed with Charlise throughout her two-day autopsy.

What they discovered was shocking.

"We were informed by the forensic pathologists that there were two bullet holes, one on her hip and then the other one was in her face," he said. 

"I mean, who shoots a little girl in the face and why?"

Hayton also found the gun Stein used to shoot Charlise.

A tip-off from the public led him to a patch of bushland, just a few kilometres from the Stein family estate.

Two firearms were found and one of them was the same weapon used to kill Charlise.

While Stein's fingerprint was found on the scope, more evidence was found at the scene.

"We had the tape on there, which was similar to the tape used on Charlise, the black plastic bags were similar and the blue tarp was similar again," Hayton said.

"So those three combined, I was pretty certain this was tied into Justin Stein."

It's been a long road for Kallista, who came face-to-face with her daughter's killer in court.

In his final despicable act, Stein claimed to the jury that he saw Kallista shoot her own daughter dead.

"As I found out that he was saying I did it, that's when I knew that he'd done this," Kallista said.

"That was another horrible moment, that I've let this person in and trusted and believed everything that he told me."

Despite all the evidence against Stein, there is still one question detectives haven't been able to answer: why?

"You'd have to dig into the dark catacombs of his mind and that's where the answers are," Doherty said.

"And unless he discloses them, we'll never find the real reason why this happened." 

Kallista can't change the past, but is working hard for a better and more peaceful future and that includes finding forgiveness for Stein.

"I forgive him not for him but for me, so he has no power over me," Kallista said.

While she's clean, she will always carry the heavy burden of what happened to her ''beautiful and kind'' daughter who "didn't deserve to have her life taken".

Watch the full story on 9Now.