Book excerpt: In July 1864, Thomas Briggs was travelling home after visiting his niece and her husband for dinner. He entered a First Class carriage on the 9.45pm Hackney service of the North London railway. At Hackney, two bank clerks entered the carriage and discovered blood in the seat cushions; also on the floor, windows and sides of the carriage. A bloodstained hat was found on the seat along with a broken link from a watch chain. The race to identify the killer and catch him as he flees on a boat to America was eagerly followed by citizens both sides of the Atlantic. Kate Colquhoun tells a gripping tale of a crime that shocked the nation. .