Arson and Explosives Squad detectives are appealing for information following an explosion at a Cranbourne skate park on Sunday evening 16 December.
Investigators have been told an explosion was heard within the vicinity of the Merinda Park skate park, which borders Endeavour Drive and rear properties of Blaxland Avenue, about 10.15pm.
The alarm was raised when nearby residents heard the loud noise and felt their houses shake.
Detectives believe an improvised explosive device was placed on one of the skateboard ramps causing extensive damage.
A hole was blown through the solid steel structure base and damage caused to the steel mesh wall frame.
Police have released CCTV of the explosion and vision of three males riding bikes within the vicinity of the skate park around the time of the explosion and are appealing for them to come forward.
They are looking to determine their involvement if any in the incident and or establish their reasons for being there.
The males are all described as caucasian in appearance and are believed to be aged between 15 to 25 years with slim builds.
The first male had short dark hair and was wearing shorts and a singlet top. The second was wearing a baseball cap, t-shirt and shorts and the third also wearing a baseball cap, t-shirt and long pants.
Investigators are also appealing for residents to check their yards for any shrapnel, metal pieces or fragments that may have come from the device and to not touch them but to call police.
Anyone with information or anyone who may have witnessed the incident or someone acting suspiciously is urged to contact Crime Stoppers on 1800 333 000 or log onto www.crimestoppers.com.au.