Mother and son dead in house fire at Woodridge, south of Brisbane

An elderly woman who died alongside her son after becoming trapped in a fierce house fire in Queensland has been identified as a tireless advocate for vulnerable people whose daughter’s cold-case murder remains unsolved.

Carmel Pierce, aged in her 80s, and her son Marcus, aged in his 60s, were found dead in their Woodridge home in Logan after it was engulfed in flames about 6pm on Sunday.

The cause of the fire is unknown but it is not being treated as suspicious.

Pierce - who publicly appealed for information on the 1988 murder of her 26-year-old daughter Cary-Jane - has died without her daughter’s killer being brought to justice.

The body of Cary-Jane, a mother of one, was found near Brisbane’s Gateway Bridge.

She had been bashed with a rock, according to police.

“A strap from the canvas knapsack she was carrying was found bound tightly around her neck,” a police file about the case reads.

A $250,000 reward has been offered for information on the case.

Queensland Treasurer Cameron Dick, who knew Pierce, was among the people to lay flowers at the scene of the fire on Monday.

“She’s a wonderful person, she had become very unwell in her later years,” he told reporters.

“She’d been very helpful to me as a local member of parliament. She’d been very supportive of me personally.”

Dick said the tragedy was a “terrible blow for the community”.

“You had a son caring for his mother and that they would both lose their lives in these terrible circumstances,” he said.

Police are investigating the cause of the fire and are asking anyone with information to contact them.

- with AAP