Lake Macquarie police last month released details of a green Holden Torana, which detectives believe could be linked to the disappearance of Robyn Hickie, 18, and Amanda Robinson, 14, who each vanished in 1979.

Lake Macquarie police have been re-investigating the suspected murders of Robyn, Amanda and Gordana Kotevski - a 16-year-old who was snatched from a suburban street in 1994.

Meanwhile, as the Newcastle Herald reported in July, Unsolved Homicide Squad detectives are re-examining another decades-old case - the murder of 22-year-old Melissa Hunt.

Ms Hunt's brutally bashed body was found in a Hunter dam in April, 1994 - seven months before Gordana Kotevski was taken.

The Newcastle Herald is not suggesting the cases are linked, but Ms Hunt's murder is among a handful of unsolved deaths and disappearances of young women in the region from that period.

A coronial inquest into Ms Hunt's death remains suspended.

"I heard just a few snippets of this story [the new lead in the Amanda Robinson and Robyn Hickie cases] and I was up and checking details," Ms Hunt's brother Peter Hallett told the Newcastle Herald.

"You don't realise it's there, this desire to know, for justice, but it doesn't go away.

"I think, as a family, you just look for the next thread you can tug on in the hope that something will unravel," Mr Hallett said.

"When you see cases as old or older than your own, it's a reminder that, yes there is still information to be found, the police can still pursue leads, there are people who know things and have kept their secrets."

Ms Hunt's body was found floating in Burrenjim Dam on Anzac Day, 1994.

The mother-of-two died of massive head injuries, including 11 skull fractures, and had been weighted down with sandstone rocks.

It is believed she died between three and six days earlier.

Six months later, on November 24, Gordana Kotevski was last seen walking to an aunt's house at Charlestown after spending the evening shopping with friends.

About 50 metres from her destination, the teenager was bundled into a white Toyota Hilux - she was never seen again.

On April 7, 15 years earlier, Robyn Hickie vanished on her way to meet friends at The Belmont Hotel.

She was last seen on foot at the Pacific Highway, Belmont North - she had left home about 7.15pm but never reached the pub.

A fortnight after Robyn vanished, on April 21, Amanda Robinson disappeared en route home from a school dance at Gateshead.

She was last seen walking along Lake Road at Swansea.

An inquest found that Amanda, Robyn and Gordana most likely died as a result of foul play.

Last month, Lake Macquarie police labelled a green mid-1970s model Holden Torana a "significant" lead in the investigation into the suspected murders of Amanda and Robyn.

"There could be someone who has knowledge of that vehicle or a vehicle fitting that description who may not have come forward back then," Lake Macquarie crime manager Detective Chief Inspector Greg Thomas said at the time, in relation to the green Torana.

"Any piece of information that they do have could be significant to the ongoing investigation."

Anyone with information about any of these cases can contact Crime Stoppers on 1800 333 000.

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