Police have said it is "extremely lucky" nobody was killed when an improvised explosive device launched from a vacant block of land tore through the roof of a nearby home in south-east Melbourne.
Detective Senior Constable Heath Lyon said about 15 seconds passed between the sound of an explosion at Carrum Downs and the moment a projectile built from a 7-kilogram metal tube crashed through the ceiling of a Hillview Drive home.
"The occupants stated the son is usually home from work at that time and would be normally showering, so he could have very easily been killed or seriously injured," Senior Constable Lyon said.
He said the two occupants who were inside the house at the time were not physically injured.
"[It is] extremely lucky no-one was killed … that time of the day there's people walking after school, walking their dogs."
The Arson and Explosives Squad has appealed for the public's help in identifying a young man and woman, who were seen walking away from the vacant block shortly before the explosion about 5:00pm on August 28.
Senior Constable Lyon said he was unsure what might have motivated someone to launch the potentially lethal missile.
"Intentions can vary from just skylarking to more of a serious nature of intentionally firing it at someone or a property and once again until we speak to these people I won't know what their intentions were," he said.
The man was described as Caucasian in appearance, about 180 centimetres tall and with a medium build.
The woman was also described as Caucasian in appearance with a medium build and long hair tied in a ponytail.
Senior Constable Lyon said those responsible for launching the projectile would face serious charges which could include possessing an explosive substance and conduct endangering a life.
When asked about reports that similar loud bangs had been heard in the area recently, he said police were open to inquiries that there could be a second incident.
Police urged anyone with information to contact Crime Stoppers.
