COLD CASE: Plea for answers ‘before it is too late’

Marilyn Wallman’s killer is still walking free despite a $500,000 reward on offer for 12 months. Her family desperately seeks answers before it is too late.

MARILYN Wallman's killer is still walking free despite a $500,000 reward on offer for 12 months for any information leading to a conviction.

It is one of Queensland's longest running child abduction cases and, in a rare move last year, police doubled the amount in the hope it would elicit the final shred of evidence needed to bring the schoolgirl's killer to justice.

"We don't need a real lot more, we just need something else," Marilyn's brother David Wallman said.

The temporary increase lapsed at the end of August this year and the reward returned to $250,000.

Mr Wallman recently met with Mackay police but said he was told unfortunately the timeframe for the higher reward could not be extended.

"We were sort of hoping a little bit more might have come out while the reward was up there," Mr Wallman said.

"Information is still coming in slowly … we've advanced a bit further at this stage … so hopefully the reward going back to the original amount doesn't deter people coming forward."

Mr Wallman said it was cowardly at this point for people with information to remain silent.

"It's depressing when you know that people do know and … they just don't want to step forward and give the vital information to us," he said.

Mackay - Day II

Marilyn's story is hard to forget - the 14 year old was riding her bike to the school bus when she vanished near Wallmans and Eimeo Rds on March 21, 1972.

Her brothers Rex and David, who followed the same route shortly after, found her bicycle and school bag.

As David ran home to tell their mother, Rex heard muffled screams, voices and noises from the canefield as he waited near her bike.

It's now more than 47 years later, but David Wallman said "the vision and the memories are only like yesterday".

"I want to find answers for mum and dad. I want to find my sister and I'd like to know what happened before there is no information left," Mr Wallman said.

"I have gone through myself, and I know the rest of the family has at different stages, a real battle of depression because you're always thinking of something you could have done at the time."

Mackay - Day II

Two years after her disappearance a skull fragment was found at Mirani Mount Ossa Rd, roughly 40km from where she went missing - in 2015 modern DNA testing identified it belonged to Marilyn.

Detectives last year revealed they believed they knew who was responsible and that there was a person of interest in Mackay who could help solve the crime - they are still tirelessly working on gathering those final pieces of evidence.

BSM - Mackay Cold Case

Over the past almost five decades there have been glimmers of hope, but for the family, not knowing, does not get easier.

"Slim hope is left - people are ageing," Mr Wallman said.

"If we can get some information from the public who have knowledge, I believe we could get an arrest.

"I believe somebody somewhere knows something.

"That little tiny bit of information could just be the final piece of the puzzle."