Nearly every car parked in a residential Sunbury court was ransacked last week.
Police said cars parked in Kerri Court were targeted in a crime spree across the town in the early hours last Thursday.
Senior Constable Troy Farley said the ransacked cars included several that owners claimed were locked. He said police believe a device may have been used to open them without leaving a mark.
Cash and various items were stolen from the vehicles, including a laptop and an iPad.
In a separate incident, a motor vehicle was stolen from Gap Road and a 6 x 4 trailer was taken from another street on the same night.
In Harcombe Drive, petrol was siphoned from a vehicle. Tools were also stolen from a container at the tip on Riddell Road in Sunbury.
Senior Constable Farley said there was “no doubt” the series of incidents were related.
He said Sunbury police had several suspects.
The crime spree has prompted police to issue a warning to people to ensure they did not leave valuables in their cars.
“Lock and double-lock cars,” Senior Constable Foley said. “And don’t leave any valuables.”
Last month, vehicle owners reported thefts from cars, including those that were locked, in Gisborne, Kyneton and Malmsbury.
Senior Constable Farley said any information, even something that seemed insignificant, could be of use to police investigating the crimes.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au.