A possible breakthrough in the investigation of Karen Ristevski's death has sparked further searches of the Mount Macedon area outside of Melbourne.
Ms Ristevski, 47, was reported missing on June 30 2016 after her husband Borce Ristevski last saw her at their Avondale Heights home.
Her body was discovered in bushland in Macedon Regional Park in February.
Information given to investigators in recent days confirms the sighting of Ms Ristevski's black Mercedes-Benz in the vicinity of Childers Road and Mount Macedon Road at about midday on the day she went missing.
A witness saw a lone male near the car, and police stressed it was reported this before the body was discovered, about 1.5km away.
On Thursday police said the importance of this information could not be overstated.
A fresh search of the route they believe Ms Ristevski's car drove will begin on Thursday.