Boroondara Crime Investigation Unit detectives are investigating the circumstances following a significant unit fire in Hawthorn last week.
Emergency services were called to the blaze at a block of units on Barkers Road on Thursday, 10 April about 4.20am.
It is understood the units were unoccupied however nearby properties became under threat when the fire began to spread.
An arson chemist attended and assessed the scene where they subsequently determined the fire to be suspicious.
Investigations are ongoing into the cause of the fire and detectives are appealing for anyone with information to come forward.
Anyone who witnessed the incident, has CCTV/dashcam footage or information is urged to contact Crime Stoppers on 1800 333 000 or www.crimestoppersvic.com.au
