The Daughters of the Night by Edgar Wallace

Mr Stephen Sanderson had had a bulky letter by the American mail and had sat up half the night writing, taking notes and comparing the new data he had received from Frank Cameron's friend with the voluminous matter he had already classified and tabulated.

It was a long work, but it was a labour of love for Stephen Sanderson. It meant the careful reading of thousands of newspaper extracts dealing with the wave of crime which had swept over England and France that year. It meant the comparison of methods thus recorded, with those which had been supplied him by the report which had come from New York. He had worked until the daylight filtered greyly through the curtained window with a dozen portraits of men and women outspread on the table before him. He was piecing together with amazing patience the pieces of the most fascinating jigsaw puzzle. Only one or two pieces did not fit, and he arose after four hours' sleep, refreshed and thrilled by the thought that even these elusive scraps might yet be fitted into the picture.