They jumped into his lime green 1977 Bedford CF van and hit the road.
But Michelle never made it home, and Stephen didn t get to the snow. After August 25, 1978, they were never seen again.
In 2005 an inquest found the pair died, but how or when remains a mystery to this day.
In January of this year, the case was referred to the State Crime Command s Homicide Squad, and a formal review was conducted.
A re-investigation was launched which involved a two-day search in the Ku-Ring-Gai National Park in June for vehicle parts after a tip-off.
These parts were found but were not linked to the couple.