The Laughing Dog: An Inspector Knollis Mystery

Madeleine Burke is prepared to swear that she was Dr. Challoner's last patient on Tuesday evening, and that he was alive and in good spirits when she bade him good night.

While holidaying in Algiers, Hugh Challoner encounters the lightning-sketch artist Aubrey Highton. Highton is desirous of finding a job back in England, and Challoner agrees to help--but then his enigmatic new friend disappears.

Back in England, Dr. Challoner is strangled in his own surgery, and it is discovered that Highton...