The enduring mystery of Susan Thomson’s life and disappearance

The message was simple.

“RING 000. WE ARE BOTH DEAD. MUM IN BEDROOM. ME IN SHED. THANKS.”

The sign was crudely taped above the electricity meter under the sprawling Queenslander that was home to Arthur Thomson, 64, in the small farming district of Cushnie, halfway between Kingaroy and Murgon in…