Police investigating if son who perished with parents in house fire tragedy was responsible

Queensland Police are investigating whether a house fire north of Brisbane, which killed two parents and their adult son, was deliberately lit.

Ros Thomson lived at her Everton Hills home with her son Dylan.

Friends said ex-husband Graeme was visiting for the weekend to help Dylan, aged in his 20s, with mental health issues.

Graeme was an SES volunteer in the Whitsundays while his ex-wife was an avid motorbike rider. They are believed to have separated on good terms.

Police are investigating neighbours' claims there was shouting coming from the home before explosions leading to the fire.

They are also investigating whether Dylan lit the fires, killing his parents and himself.

They continued the search for answers on Wednesday, calling in SES crews and scouring neighbours' properties for more evidence.

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Queensland Police Detective Acting Inspector Joe Zitny said authorities are “canvassing neighbours and associates”.

“We have a significant number of detectives working on this matter,” he said.

Anyone with information is encouraged to call Crime Stoppers 1800 333 000 or use the Crime Stoppers online reporting page.