Police charged Anthony Robert Harvey with the murders of his two-year-old twins Alice and Beatrix, his three-year-old daughter Charlotte and his 41-year-old wife Mara in the southwestern city of Perth.
Police said up to five bodies had been found at the scene when police arrived at noon. Investigators were still there.
The passenger on the QF9 Boeing 787-9 Dreamliner was reportedly handcuffed, masked, and removed by police after the plane returned to Perth on Saturday night.
Sayed Abbas, 35, was pivotal in organising the transport of the asylum seekers coming from Indonesia on three overcrowded boats in 2009 and 2011.
Malaysia's transport minister on Monday met a group representing families of passengers from missing Malaysia Airlines Flight MH370 in Perth, after being lobbied by relatives of those lost when the plane vanished in 2014.
Australia’s Cameron McEvoy sent out a message to his Olympic rivals with a scorching personal best to beat former world champion James Magnussen into second place in the 100m freestyle at the Perth Aquatic Super Series.
A bushfire destroyed nearly 100 homes in Western Australia as it swept through countryside south of Perth, but there were no casualties reported.