Three Melton teenagers have been arrested following the fatal fire in a Sunshine factory in February.
Four warrants were executed at 6am on Tuesday at residential addresses in Kurunjang and Melton South.
It follows the February fire at a Bunnett Street business on February 23, where two men died at the scene.
On Tuesday, three men were taken into custody and will now be interviewed by police, including a 19-year-old Melton South man, a 19-year-old Kurunjang man and an 18-year-old Melton South man.
A gel blaster was seized from the Kurunjang address, while police located a sword, two machetes, two knives and a quantity of what appears to be cannabis at one of the Melton South addresses.
Investigators have been told a white dual cab ute pulled up outside the business at 3.51am on February 23, before a male exits the vehicle, emptying the contents of a jerry can on the factory door before igniting it.
He returns to the waiting vehicle as the building goes up in flames, and they flee the scene.
The fire subsequently spread to a building behind the panel shop, a factory on Marshall Street, where two people were sleeping inside at the time.
The two men, a 42-year-old and a 48-year-old both from Sunshine North, died at the scene.