Crabtree’s daughter was found dead in September 2012, at a Maudsland home in Queensland, while her brother’s body was found at an Upper Coomera home five years later, in July 2017.
Both siblings had disabilities and died after being forced to take prescription medication, reported the news station, citing police.
Police believe the killings were pre-meditated and financially motivated.
Before and after Erin’s death, Crabtree allegedly received about $458,396 (AU$567,863) from two insurance claims meant for the care of her children. She then allegedly made another two unsuccessful insurance claims in 2017 to cover permanent disability and death—which could have seen her receiving a further $293,024 (AU$363,000).
At the time of the claims, police were not suspicious of the siblings’ deaths but an investigation was launched after new information was received, reported Nine News.
Detective Inspector Mark Thompson said the investigation has been complex, as some of the alleged incidents occurred across Australia.
“That is why we are appealing for anyone who may have any information that could assist with the investigation,” Thompson said.
“Any piece of information, no matter how small, can have a significant impact on our investigation,” he added.