Would-be carjackers have used red and blue flashing lights on the front of their car in an attempt to steal a car from a woman in Craigieburn.
The woman was driving on the Hume Highway, near Rushwood Drive, about 8.20pm on August 16 when she was intercepted by a silver VE Holden with red and blue flashing lights.
The woman pulled over, thinking it was the police, and four men from the car approached her vehicle.
Police said the men demanded she hand over her car – a Mitsubishi Lancer hatchback – and attempted to enter the vehicle.
She drove off and the four men returned to their car and followed her south along the Hume Freeway.
The men were last seen driving along Cooper Street.
The four men are believed to be of African appearance.
Hume Crime Investigations Unit detectives are advising anyone who is unsure about the vehicle involved in an intercept to call triple-0 immediately or drive to their nearest police station.
Anyone with information about the four men or the attempted carjacking is being asked to call Crime Stoppers on 1800 333 000.