It's been almost 20 years since three people perished in a series of deliberately lit bushfires in Melbourne's Dandenong Ranges.
Graham Lindroth, 26, and his wife Jennifer, 24, died on January 21, 1997 while seeking shelter under their Ferny Creek home.
The body of a neighbour, Genevieve Erin, 50, was also found in their home where she had fled for shelter.
A total of 42 houses were destroyed, 34 of them in Ferny Creek, and another 45 damaged, leaving a repair bill of $6.5 million.
Despite extensive investigations, police have been unable to locate anyone responsible for the fatal fires.
The Arson and Explosive Squad is now looking at the fire with fresh eyes and hope a $1 million reward will help bring anyone with information forward.
"We believe whoever lit those fires chose the perfect day and there was a definite intent to cause extensive damage," Arson Squad Inspector Michael Roberts said.
"By making a renewed appeal to the public and finding the person responsible for such senseless devastation, we are hoping to provide the families of the victims with some answers."
A reward of up to $1 million will be paid for information leading to the apprehension and subsequent conviction of the person or persons responsible for the suspicious fires.
Police previously posted rewards of $100,000 in 2002, and $50,000 in 1999, for information leading to arrest and conviction but are yet to charge anyone over the fatal fires.