Australian police are investigating whether a Brisbane car fire that killed a family of five was a murder-suicide

Ex-Warriors player Rowan Baxter and his three children died at the scene yesterday and his wife Hannah died later in hospital.

Sky News reporter Anna Rawlings says it's understood the couple was in a custody battle over the three children, who were all under 10.

She says authorities are looking into reports an accelerant was used, and are calling for any witnesses to come forward.

Locals who saw the tragedy are being offered counselling.