The paedophile who killed Samantha Knight could be released from prison.

“I forgive him. I don’t want him in my life. Me carrying around a hate towards him means I won’t let him go.”

These are the words of 28-year-old Chantelle. She is speaking about 66-year-old Michael Anthony Guider; the man who babysat her and her best friend in Sydney’s beach-side suburb of Manly when she was six-years-old. Who let the girls buy lollies from the corner store, and Coca-Cola, too. “I was never allowed to drink Coke,” Chantelle recalls. In the soft drink, Guider put the drug Normison, which knocked the girls unconscious. While they were passed out, he molested them and took photographs. They were with him for a weekend.

“He got us naked and touched us and got us to touch each other,” she told reporter Ross Coulthart in tonight’s episode of 60 Minutes. “I remember being really aware at one moment after not being aware for a long time. I was looking out of second story window thinking ‘I just want to get out’. I knew it was really really unsafe. I couldn’t leave.”

Why is Chantelle speaking out now? Later this month, Guider is eligible for parole. “I’ll do anything I can to keep him locked up,” she said.

Chantelle is convinced he will re-offend if released.

“With 100 per cent certainty, if [they] release Guider [they] are putting many little girl’s lives at risk.”

Chantelle and her mum went to the police and, in 1996, Guider was imprisoned on sixty charges of child sexual abuse. In his possession police found hundreds of photographs of children being sexually assaulted. There were at least nine girls and two boys.

Samantha Knight was another young girl. Her story took place 10 years before Chantelle’s did.

It was August 19 1986, and nine-year-old Samantha had been at school at Bronte Primary in Sydney’s Eastern Suburbs. After school finished, she went home to her mother’s apartment in Bondi where she changed clothes. She walked to the shops down the road and bought a pencil and some lollies. She had lost her front door key, so stayed out until around 6:30pm when witnesses saw her starting to make her way back home.

Guider – a man she and her mother had known, a gardener who also appeared on television sometimes – picked her up. He offered her a drink. She became unconscious. But something else went wrong.

"He confessed he'd picked up a child called Sam," a Dutchman called Frank Soonius, otherwise known as Witness O, told 60 Minutes. Frank was in prison at the same time as Guider. He was convicted for drug smuggling and he and Guider would spend their days playing chess.

"He said he'd taken her to a shed and drugged her but things didn't go according to plan," Soonius continued. "She woke up and she recognised it was Michael. He probably panicked. Probably strangled her because she called him by his name."

Knight's body was never found. "He said he put her in a garbage bin and put the rubbish on top. He took her to where the rubbish goes and put her there," Soonius said.

But none of this came out until years later.

While he'd been in prison, police had been investigating Guider's link to Samantha's disappearance. Photos of her were found in his collection. In them, she was clearly drugged. He also had a scrapbook filled with news clippings about her disappearance. The pressure became to much in 2002 when Guider cut a deal and pleaded guilty to Samantha's manslaughter. He said she died accidentally because of the drugs he'd given her.

Guider was sentenced to an additional 17 years behind bars, with a non-parole period of 12 years. In 2014, his application for parole was denied. Chantelle hopes it is the same this time. Every year she writes to the parole board, begging them to keep him locked up.

"Thank God it wasn't me, and how horrible for Samantha and her family. That's why he shouldn't get out."

Still, no one knows where Samantha's body is.

"He just won't tell us. He might have something to hide, or he might just be so scared once he delivers one final piece of information he has nothing more to offer to anybody," police inspector Darren Sly, who lead the investigation into Samantha's disappearance, told 60 Minutes. 

Sly describes the day of Samantha's abduction as the "day Australia lost its innocence".

"From that time on, people have had an awareness," he said. "It's changed the way we've raised our kids."