Firebugs struck at Pakenham Springs Primary School for the second time in two months.
Police were called to a skip bin fire that was believed to have been lit about 11.15pm on Friday 27 January.
CCTV captured four men walking within the fenced area of the school and taking off down Livingstone Boulevard towards Heritage Boulevard.
The fire is being treated as suspicious and police are conducting an investigation.
This incident came one month after two men helped to extinguish the flames of a small fire at the school playground, which they noticed about 8am on Sunday 4 December.
A bin had been tipped over on its side and it appeared that someone had set the rubbish on fire in the early hours of the morning in a quiet corner underneath some playground equipment.
Police have urged anyone with information to contact Crime Stoppers on 1800 333 000.
