The police investigation into the fate of missing Melbourne mother Karen Ristevski has uncovered fresh clues relating to her disappearance in late June.

Mobile phone data uncovered in a police probe shows Mrs Ristevski’s phone was detected 40km northwest of her Avondale Heights home hours after she vanished on June 29.

The 47-year-old’s phone is understood to have been detected by transmitter towers located on the Calder Highway, near Gisborne.

Karen Ristevski (left), and search crews (right). (AAP)

Missing Melbourne mother Karen Ristevski with husband Borce; Calder Highway, near Gisborne. (Supplied/Google Maps)

Mrs Ristevski was last seen at 10am, prior to leaving her home, following a purported fight with husband Borce Ristevski over money matters.

Mr Ristevski’s phone has since been found to have “pinged” towers on Calder Highway near the suburb of Diggers Rest, approximately 20km northwest of his home.

That data has also indicated Mr Ristevski’s phone was switched off for about two hours on the same day.

When questioned by police, Mr Ristevski said he had driven his wife’s 2004 Mercedes-Benz that day in an attempt to fix a faulty fuel gauge, before returning home.

On Thursday, A Current Affair revealed that Mrs Ristevski’s stepson Anthony Rickard had spoken to several media outlets in an attempt to sell an exclusive interview regarding his relationship with Mrs Ristevski for $200,000 – a claim which he has since denied .

In a series of Facebook posts released by the Daily Mail , Mr Rickard denounces his father, claiming he “allowed Karen to continue her fantasy of leaving you to run away with me”.

Mr Rickard has spoken publicly about being questioned by detectives regarding his stepmother’s disappearance and denied killing her, saying that he “would have liked to”.

Mrs Ristevski’s brother-in-law Vasko Ristevski claimed earlier this week the missing mother may have fled overseas.

The investigation continues.