Queensland detectives trying to solve the 1972 murder of Mackay teenager Marilyn Wallman hope a larger reward will root out her killer.
The 14-year-old was last seen 46 years ago, on March 21, when she climbed onto her bike for the ride from her Mackay home to her school.
A piece of her skull was found in the nearby town of Mirani two years later, but it was only identified as Marilyn’s in 2015.
Police Minister Mark Ryan MP will on Tuesday announce a significant increase to the reward on offer to find the person who killed her.
Marilyn’s family has been tormented by the lack of answers, particularly her brothers who were riding about 10 minutes behind their sister on that fateful day.
As they followed the route she’d taken towards their school, they found her bike and school bag abandoned in the street.
In 2016, brother Rex Wallman said his family had not given up hope that the killer would be caught.
At the time police appealed for information about a two-tone aqua and white Holden sedan, believed to be a HD or HR model, that was spotted near where Marilyn vanished.
© AAP 2018