In NSW, a mounted policeman finds a young woman wandering in a flooded swamp, and is piqued at her refusal to give him information about herself. Reading a notice about a runaway woman and child, and finding a child's body floating in the flooded river when he returns to the swamp, he concludes she is a murdress. The additional evidence he finds and the denoument reveal the dangers of circumstantial evidence. (PB)