Detectives believe a car fire in Melbourne's north is likely linked to a series of dangerous arson attacks on tobacco stores.
Police were called to the car fire at the corner of East Street and Middle Street at Hadfield about 3.10am on Tuesday.
The blaze spread to a fruit and vegetable shop, which sustained significant damage, Victoria Police said.
Investigators urged people who saw anyone acting suspiciously in the area or a silver Volkswagen Jetta or white Audi about the time of the fire to come forward.
The blaze is believed to be connected to arson attacks on tobacco stores in Victoria orchestrated by Middle Eastern organised crime syndicates behind the state's illegal tobacco trade.
The syndicates have paid lower-level criminals to firebomb businesses in revenge attacks if tobacconists don't comply with their extortion attempts, police allege.
"This is inherently dangerous behaviour and I want to assure the public that police will not tolerate such blatant and dangerous criminal conduct in our communities," Detective Inspector Chris Murray said on Tuesday.
Police earlier this month charged three men and a woman with causing damage by arson over the series of blazes linked to the illegal tobacco trade.
At the time of the charges, police alleged there was 11 linked fires, and the quartet were simply "puppets for those pulling the strings".
The 11 attacks included a blaze at a Springvale store on March 24, repeated fires at a Moonee Ponds store in May and June, fires at two stores at Deer Park in July, a fire at a Wodonga store on July 27 and a blaze on the same morning at Wangaratta.
A tobacco store on Hogans Road at Hoppers Crossing in Melbourne's southwest was also targeted on August 11.
The arrests followed raids at a business and homes at Heidelberg, Kilmore, Flemington, Derrimut, Broadmeadows, Pascoe Vale and Glenroy.
Police have been visiting dozens of tobacconists in Victoria to get information about who is behind the attacks.