For 40 years, police thought Ivan Milat murdered two missing teens. Now, they have a new theory.

Forty years after teenagers Amanda Robinson and Robyn Hickie disappeared from the Pacific Highway near Newcastle, NSW, police have a new lead. Is it possible that their families could find some closure, after all this time?

Eighteen-year-old dental nurse Robyn was last seen at a bus stop in Belmont North on April 7, 1979. She was on her way to catch up with a netball teammate.

Fourteen-year-old schoolgirl Amanda was last seen at a bus stop in Swansea just two weeks later. She had been at a dance at her high school.

Amanda’s mum Anne had only let her daughter go to the dance because she had arranged a ride home with a friend’s father. But Amanda had missed the ride and had caught the bus instead.

She got off the bus just a few hundred metres from her home and waved to some friends. She was never seen again.

“She was only a little girl who had just turned 14,” Anne told Woman’s Day in April this year. “And she wasn’t a worldly little girl either.”

Anne found out the next morning that her daughter hadn’t made it home.

“You age 20 years in the first second you hear. And it doesn’t get any easier.”

No one has been arrested over either disappearance.

In 2001, an inquest began into the disappearances of Robyn and Amanda, as well as Leanne Goodall, who was 20 when she went missing from the Star Hotel in Newcastle on December 30, 1978.

The State Coroner, John Abernethy, blasted the police’s handling of the original investigations, saying it was “extraordinary” that leads weren’t followed up, statements weren’t taken and detectives were taken off the unsolved cases.

In Leanne’s case, local police assumed she was a runaway and no formal investigation was carried out.

In Robyn’s case, police labelled her “a known hitchhiker”. They only took two statements and ended the investigation after just two weeks.

As for Amanda, her case was taken more seriously because she was so young. Two detectives came from Sydney to investigate her disappearance.

But they were told to concentrate exclusively on her case, so they didn’t explore any possible links with Robyn’s disappearance just two weeks earlier. The Sydney detectives were recalled after two weeks, and local police didn’t follow up any of their suggested lines of inquiry.

Six persons of interest gave evidence at the inquest. One of them was backpacker killer Ivan Milat. He had been employed as a roadworker in the Hunter region in the late 1970s, and one of the places he had stayed had been the Star Hotel.

But he denied having anything to do with the disappearance of the three girls.

In a moment of breathtaking cruelty, he leaned forward and stared at the parents, saying, “I could ask how they let a 14-year-old run around at midnight.”

Mamamia’s True Crime Conversations explore what you don’t know about the widely-known serial killer, Ivan Milat. Post continues below.

At the time of the inquest, Robyn’s father Jim said he was grateful for the intensive police work in recent years but believes it came too late.

“There was no hope from the start because they didn’t put the effort in when Robyn went missing,” he told the Sydney Morning Herald. “First of all they wanted to believe that our daughter was a runaway.”

He said he felt his daughter’s case and that of the other girls would just lie in the police records.

“Unless someone comes up with a confession, nothing will happen. That’s the truth in the matter.”

In his findings, the Coroner said he was satisfied that Leanne, Robyn and Amanda were dead, despite their bodies never having been found. He said that “a person or persons unknown” were responsible for their deaths.

After the inquest, Leanne’s family held a memorial service. Amanda’s family didn’t.

“I need proof first,” Amanda’s mother Anne said to the Newcastle Herald in 2009. “We are just in limbo. We are in this terrible place and there are no words to describe it. After this long it is not going to be good news but you can’t give up hope.”

Amanda’s father Ronnie told the Newcastle Herald he needed to know who was responsible.

“It is not just where she is, it is what happened to her. I still want to know.”

In June this year, police announced the formation of a new strike force to look into the disappearance of Amanda and Robyn, as well as Gordana Kotevski, a 16-year-old high-school student who disappeared from Charlestown on November 24, 1994, after going late-night shopping with friends.

Gordana was seen being bundled into a white car, and witnesses heard screams.

“I hope to God they get answers for some of us,” Anne said to the Newcastle Herald when the strike force was announced. “It’s hell on earth, heartache and suffering for 40 years.”

This week, police released a photo of a green 1970s Holden Torana sedan similar to one they believe may be linked to Amanda and Robyn’s disappearances. Detective Chief Inspector Greg Thomas said it was a significant new lead.

“We understand it’s been 40 years since Robyn and Amanda’s disappearances, however, we are seeking assistance from anyone who may even have moved to a different state or who may have some memory of this vehicle to come forward to police,” he added.

Detective Chief Inspector Thomas said the Torana may have travelled between Lake Macquarie and Queensland.

The Daily Telegraph is reporting that a 58-year-old businessman living on the Gold Coast, who used to live in the Hunter Valley, is being investigated in relation to the disappearances of Amanda and Robyn. Police are not commenting on the report.