A green Holden Torana has become a major focus of an investigation into the disappearance and suspected murder of two teenage girls from Lake Macquarie 40 years ago.
Detectives released details of the car, which they believe to be a "significant" lead in the decades-old cases, on Monday.
Investigators have been re-examining the 1979 disappearances of Amanda Robinson, 14, Robyn Hickie, 18, and 16-year-old Gordana Kotevski, who vanished in 1994.
Police said on Monday detectives believed a green, mid 1970s-model Holden Torana - which they think was in the Lake Macquarie area when Amanda and Robyn disappeared - was key line of inquiry.
"That's 40 years ago, I understand, but investigators believe there may be people who lived in the Lake Macquarie area back at that time, who may still live in the area or who may have moved elsewhere interstate, that may have some knowledge or piece of information that could be integral to the ongoing investigation," Detective Chief Inspector Greg Thomas told reporters at Belmont Police Station.
"There could be someone who has knowledge of that vehicle or a vehicle fitting that description who may not have come forward back then. Any piece of information that they do have could be significant to the ongoing investigation."
Detective Chief Inspector Thomas would not comment on reports that police had also identified a 58-year-old man on the Gold Coast, who formerly lived in the Hunter, as a person of interest in the disappearances of Amanda and Robyn.
But he said investigators believed the Torana may have travelled interstate between Lake Macquarie and Queensland.
"The car has become a focus - not the sole focus - but a focus of investigators," Detective Chief Inspector Thomas said.
Robyn Hickie was last seen on the Pacific Highway at Belmont North on the evening of April 7, 1979.
She was a short distance from her home and had left about 7.15pm to meet with friends at The Belmont Hotel, but she never arrived.
Amanda Robinson vanished two weeks later - she was last seen at Swansea, walking home along Lake Road after a school dance at Gateshead.
While the disappearances of Amanda and Robyn are being re-investigated alongside that of Gordana Kotevski - who was snatched at Charlestown in 1994 and never seen again - police said the Torana did not appear relevant to Gordana's case.
An inquest that each of the girls died, most likely as a result of foul play, but no-one has been charged in the years since they vanished.
A team of four detectives has been re-investigating the suspected murders of Amanda, Robyn and Gordana under the banner of Strike Force Arapaina since April.
Detective Chief Inspector Thomas said on Monday the re-examination had been "comprehensive" so far.
He urged anyone with information that could help detectives to contact police - even anonymously through Crime Stoppers if necessary.
"It may seem like small or insignificant information from decades past, but it could help investigators solve these cases," he said.
