A key piece of evidence has been sent to the United States in a bid to find missing Melbourne mother Karen Ristevski.
Ms Ristevski, 47, has not been seen since June 29 when she left her Avondale Heights home after an argument with her husband Borce.
She has not used her bank accounts or phone since.
The Herald Sun reports Victoria Police have sent a potentially important piece of evidence to the US and is re-examining hundreds of hours of CCTV footage in an effort to find out what happened to her.
The newspaper also says investigators have again spoken to Mr Ristevski and his estranged son, Anthony Rickard.
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Police remained tight-lipped on the case on Monday.
"The investigation remains active and ongoing. We will not be providing a running commentary on the case," Victoria Police spokesman Luke Zammit told AAP.
Water police have conducted numerous searches in the Maribyrnong River and the Murray River at Barmah in search of the missing mum.
In August, police asked residents on rural areas northwest of Melbourne to check for any suspicious changes on their land.
Investigators also took the unusual step to call on anyone who had information, including family members or people that knew the Ristevski family, to have the "courage" to come forward.
