Fifty years after 14-year-old Marilyn Wallman disappeared from a rural Mackay road, her family are calling for a $1 million reward in a final bid to find out what happened to their "beautiful, caring" daughter and sister.
Only a fragment of bone from Marilyn's body has ever been found, and despite a long-standing $250,000 reward, police investigations and public pleas, her family still does not know what happened to her.
Marilyn's brother Rex Wallman remembers his older sister as a loving and vibrant girl, keen on sports, protective and caring of him and siblings David and Lenore.
"I know she was only 14, but at home, growing up on the farm, we were just trying to make ends meet. Mum and Dad had to be busy just trying to run the farm and earn an income for us," Rex said.
"Marilyn was there as a mother figure … to look after David and myself, and Lenore when she came along. She was always there looking out for us."
Photos show a kind-eyed, smiling young girl with bobbed hair, cheerful and open-faced. Marilyn was sporty, active, playing with Rex and David for hours in their backyard.
"I can remember just laying in the backyard in the grass and just looking up at the clouds, laughing and making shapes out of clouds, just talking about stuff. It was great fun," Rex said.
'She would have been there for us'
On the morning of March 21, 1972, Marilyn Wallman cycled off, eager to catch the bus in time for the school sports day.
Rex and David followed along 10 minutes later, hoping to catch up with her. But the brothers came across Marilyn's pushbike on the side of the road and her school bag half-opened.
Rex later reported hearing muffled screams coming from the cane paddock on the side of the road.
A massive search began, but Marilyn had vanished.
No one has ever been charged with Marilyn's disappearance or murder.
Two years later, bone fragments were discovered 40 kilometres west of her last known location. In 2015, a fragment was confirmed by the Queensland coroner as belonging to Marilyn.
Queensland police posted a reward of $250,000 for information that would lead to an arrest. In 2018, for just 12 months, the reward was increased to $500,000.
If Marilyn were here now, Rex said, she would be the "beautiful, caring person" she was before she was taken.
"It's something we often talk about as a family, and wonder what life would be like if she were still here. Who she would have married, kids and the like," Rex said.
"I know she would have been there for us in all the things we go through in our lives as we were growing up."
Marilyn's parents John and Daphne are now 85 years old, growing frail and increasingly fearful they will never know what happened to their little girl.
Each time the family gathers, the conversation turns back to the fact that they still have no answers.
"We have no idea what happened to her, where she went, where she is today. Nothing," Rex said.
As the 50th anniversary of Marilyn's disappearance draws near, Rex said the family wanted proper attention on Marilyn's case, and the reward increased to $1 million.
"I was talking to Mum and Dad only a week and a half ago, and Mum was very upset about the fact, worried that she's not going to get any answers and she's getting older," he said.
The DNA efforts on the single piece of bone confirmed to be from Marilyn took years to secure, and Rex believes more could now be done with the old case files and information surrounding Marilyn's murder.
$1 million reward push
In 2020, NSW Police announced another 50-year-old missing child case – that of toddler Cheryl Grimmer – was now the subject of a $1 million reward.
And in Western Australia, within days of Cleo Smith being abducted, a $1 million reward was offered for information leading to her discovery, or an arrest.
Rex wants the same attention given to his sister's case.
After lobbying from the Wallmans, in 2018 the reward for Marilyn's case was doubled to $500,000.
It was the largest government reward offered in Queensland – but it was only posted for 12 months.
Now, it once again sits at $250,000.
"A million dollars might make somebody that knows something about it come forward, with that attraction," Rex said.
University of Queensland criminologist Renee Zahnow said rewards played an important role in keeping such cases in the public eye.
"Rewards send a message to the public that this information is really valuable, or that there is a higher likelihood or hope that this case could be actually solved," Dr Zahnow said.
"It can also send a message that says the community is empowered here. We want to solve this and you've all got a role to play.
"Or that the particular crime type is something that is absolutely intolerable, like child abduction – intolerable."
Rewards also change how people think, she said.
"[Rewards] change information in terms of people's perception, from being something that is about morality to something that is a commodity," she said.
"The information that I have, I could morally give it over to the police – and that just depends on 'do I want to give that up or not?' – into 'this is a commodity I can sell'.
"When it becomes a commodity I can sell, it becomes less of this moral quagmire for people around 'where do my loyalties lie?'."
Research has also shown people responding to a reward are more likely to provide detailed and accurate information.
A request to interview a member of the Queensland police rewards evaluation committee that sets missing person rewards was declined "due to operational reasons".
Queensland Police Minister Mark Ryan was also not available for an interview.
Rare understanding
One Queensland family knows what the Wallmans are enduring.
In 2004, nearly a year after Daniel Morcombe's disappearance, Queensland issued a $250,000 reward for information about the Sunshine Coast teenager's abduction. It was one of the first times the state offered such an amount.
Five years later, that reward was temporarily lifted to $1 million through private donations.
"We were, and still are, enormously indebted to those people that put their hard-earned money on the line," Daniel's father Bruce Morcombe said.
"We were really lucky, in that it really changed from $100,000 which was the normal amount, suddenly we were able to make it a million dollars."
Through a rare understanding of what each family has endured, the Wallmans and the Morcombes have become friends.
But, Mr Morcombe said, that shared understanding was tempered by the fact that he and Daniel's mother Denise now know what happened to their son.
The Wallmans, in contrast, are still in limbo, 50 years after losing their beloved daughter, sister, and friend.
"We've been on both sides of that fence, and I can tell you which is worse. It was the first eight years, there's no question of that," Mr Morcombe said.
Mr Morcombe said that a $1 million reward did not directly lead to the case being solved, as the community had already so fiercely condemned the snatching of such a young child.
But it helped keep the case in the public eye, and gave him and his wife a "glimmer of hope" that sustained them through eight long years.
"You don't pick up a kid on the side of the road and leave the family in a terrible predicament," Mr Morcombe said.
"It doesn't matter what your past was, it was a heinous crime, and everyone wanted to contribute to that answer."
Brett Peter Cowan was arrested and charged with Daniel's abduction and murder, eight years after his disappearance.
Mr Morcombe said $250,000 in today's money might no longer be enough to push someone to come forward.
"It's not really life changing. It's generous and it's handy, but let's face it, a million dollars is going to make, perhaps, some people think twice," he said.
Bond University professor and former Queensland Police officer Terry Goldsworthy said seen from the eyes of victims' families and loved ones, the differing rewards were challenging.
"What is the rationale for [one missing person] getting one figure and someone else getting another?" Professor Goldsworthy said.
"It is problematic because people must see those [figures] as an evaluation of an offence against someone who is a loved one or relative."
'Where is Marilyn?'
Rex said the apparent injustice in some cold cases being given great rewards, or greater policing attention, is hard to take.
"It's disappointing, frustrating. You get angry," he said.
"You just get sick and tired of having to beg and plead and try and find ways around it, to convince the people in charge to spend some resources on doing an investigation."
Even at 50 years as people's memories fade or life changes, Dr Zahnow said rewards could still have an impact.
"There are cases where people might sit there. Someone is sitting there, with that [reward] document written down, printed off, waiting, waiting, waiting, thinking on it every day – 'should I go forward?'," Dr Zahnow said.
"Life changes. People die, people get divorced, people move on. People go through situations in their life that changes their moral compass."
For Rex, his thoughts keep turning to his parents John and Daphne, and their long wait for answers.
"The way that they've handled themselves and their love for one another and their remaining family over the 50 years … is just absolutely amazing," Rex said.
"They care for everybody else, put themselves last and all they ever want is to find some answers.
"What happened and where is Marilyn?
"It's just extremely sad to look at them now, as they're getting fairly old, and see the sadness in their eyes all the time, about not knowing."