Pathology, physics, ballistics, and photography, plus perseverance and brilliant detection effort, all contributed to the vast accumulation of circumstantial evidence that sent William Alfred Bayly, a 28-year-old farmer of Ruawaro, near Huntly, in the Waikato district, to the scaffold in 1934 for the brutal murder of his neighbours, 47-year-old Samuel Pender Lakey and his wife Christabel. When another neighbour on an October morning in 1933 noticed that the Lakeys' cows had not been milked and went to investigate, he set in motion a painstaking and intensive investigation that created for New Zealand new standards in police thoroughness, patience, and skill. With 50 men under canvas on the murdered couple's farm, it took the police authorities seven months to bring the man whom they believed to be guilty to trial.

Bayly was found guilty of the murder both of husband and of wife. Even at the foot of the gallows in Auckland Prison his stark composure never deserted him, and his last words were a protestation of innocence and a criticism of the purely circumstantial testimony on which he had been condemned. He was executed in July 1934, nine months after the discovery of Mrs Lakey's body in the duckpond.