Australia’s worst serial killer, Ivan Milat, was long thought to be behind the vanishing of three teenage girls from a busy NSW highway 40 years ago.

But now police have a new suspect, at least in two of the cases – a wealthy businessman who lives on the Gold Coast but often travels interstate for work.

Detectives investigating the cold case disappearance and suspected murders of the three Lake Macquarie teenagers have released an image of a vehicle similar to the one they believe might be linked to two of the cases.

It is as a distinct green, mid-1970s four-door Holden Torana sedan.

The same model of car linked to the teenagers’ disappearances. Photo: NSW Police

Robyn Hickie, 18, left her home about 7.15pm on Saturday, April 7, 1979. She was last seen standing at a bus stop on the Pacific Highway, Belmont North.

Amanda Robinson, 14, was last seen a fortnight later on Saturday, April 21, 1979. near a bus stop on Lake Road, Swansea. She was on her way home from a dance at her high school in Gateshead.

About 9pm on Thursday, November 24, 1994, Gordana Kotevski, 16, was forced into a vehicle on Powell Street, Charlestown, while walking from Charlestown Square Shopping Centre to her aunt’s home on the same road.

Despite extensive investigations at the time, and over the years, none of the girls have been located. A subsequent coronial inquest into their disappearances found that the girls were deceased, most likely as a result of foul play.

Investigators long suspected Milat was responsible, but he denied involvement at the 2002 inquest.

Milat was building roads in the area at the time.

Milat, 74, died from oesophagus and stomach cancer at Long Bay Prison Hospital in October. He had been serving seven life sentences for murders committed in the 1980s and 1990s.

Lake Macquarie Police District Crime Manager, Detective Chief Inspector Greg Thomas, said the car was a significant new lead in the hunt to find out what happened to the girls.

“We are hoping anyone who was living in the Lake Macquarie region in the late 1970s may have a recollection of this Holden Torana, in particular in the month of April 1979.

“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 – you can remain anonymous through Crime Stoppers if you wish.

“It may seem like small or insignificant information from decades past but it could help investigators solve these cases,” Detective Insector Thomas said.

-with AAP