Police attended a business property in Point Cook overnight following reports of a fire about 1.45am.
It is understood a man riding his bike past the shop front on Wallace Avenue raised the alarm after seeing the fire and that two windows of the real estate agency were smashed.
The fire is being treated as suspicious. A crime scene has been set up until fire investigators and detectives attend the scene this morning.
Anyone with information is urged to call Crime Stoppers on 1800 333 000.