Detectives have revealed they have a key suspect in relation to the murders of Karlie Pearce-Stevenson and her daughter Khandalyce Pearce-Stevenson.

A report by Fairfax Media said investigators in SA and NSW had made swift progress in the investigation, identifying a male suspect.

They reported that the man was in custody in a NSW jail, serving a prison sentence for unrelated offences.

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Since the identification of the victims, police said an enormous amount of information had been received including 30 calls from SA residents and another dozen calls from other states to Crime Stoppers.

Meanwhile, Karlie may have been dumped in Belanglo State Forest as a deliberate distraction to throw investigators “off track,” police say.

Her remains were found in the New South Wales forest in 2010 while the remains of her young daughter, Khandalyce Kiara Pearce, were found dumped more than 1100 kilometres away alongside a SA highway earlier this year.

SA Police Detective Superintendent Des Bray was asked on 891 ABC Adelaide about suggestions Ms Pearce-Stevenson may have been killed elsewhere and dumped at Belanglo as a ruse.

The forest is notorious as the former stomping ground of serial killer Ivan Milat, who was convicted in 1996 over the murders of seven young people in the area.

His nephew, Matthew Milat, was also sentenced in 2012 for killing his 17-year-old friend with an axe in the forest.

“The forest is infamous and it’s a reasonable theory to suggest the person [murder suspect] could have disposed of the body in the forest to throw us off track,” Superintendent Bray said.

Khandalyce Kiara Pearce.

“But it hasn’t, and we’re convinced that Karlie’s death has nothing to do with the previous crimes associated with the forest.”

Earlier on Thursday, Superintendent Bray said police were not willing to speak about the circumstances of the mother and daughter’s death and where they might have died.

“We’re not 100 per cent certain and if we were to speculate it might not be a good thing,” Superintendent Bray said.

“It’s really important that we put out information that’s correct.

“It’s going to take us a little while to unravel the mystery but I’m very confident, the way the investigation’s heading, we will get a result on this.”

A family leaves flowers at the shrine. Photo: ABC

Superintendent Bray said Karlie left Alice Springs in 2008 with her daughter to travel and find work.

They were last seen in November of that year, driving on the Stuart Highway near Coober Pedy.

He said their movements after that were a mystery.

Police believe they also travelled to Darwin, Adelaide and throughout the Murray and Riverland districts.

“Karlie and Khandalyce travelled extensively from Darwin through central Australia, Adelaide, probably through Victoria, Canberra and the Riverland,” Superintendent Bray said.

“So what we need is friends and associates to come forward.”

He asked owners of motels, hotels and caravan parks to check their records to see if the mother and daughter stayed at their business anytime since 2006.

A friend of the family said he used to live near the family in Alice Springs when Karlie was still “only a little kid”.

“They were really good people, salt of the earth people … she [Karlie] was a normal everyday sort of kid,” he said.

“It’s just been a sad state of affairs for the whole family.”

Karlie was named “Angel” by police after her unidentified remains were first found in 2010 after being found with a T-shirt bearing an “angelic” motif across the front.

People have returned to a roadside shrine near Wynarka where Khandalyce’s bones were found to leave flowers.

A local council has offered to cover the costs of bringing the remains of the mother and daughter home to central Australia and to pay for their funerals.

-ABC