Did Scotland Yard Know who Jack the Ripper was- and Let HIM go? The head of Scotland Yard's Criminal Investigation Department insisted they knew the identity of Jack the Ripper, but couldn't prove his guilt in court. The chief investigator on the case backed him up, as a note discovered a century later showed. So why did the police never publicly proclaim Aaron Kozminski the number one suspect in the most notorious serial-murder case of all time? And could twenty-first-century investigative techniques have helped the nineteenth-century detectives close their most famous unsolved case? Ripperologist Robert House combines historical research and contemporary criminal profiling techniques to offer a compelling solution to one of the most vexing criminal mysteries of all time. He demonstrates that Kozminski had the means, the motive, and the opportunity to commit the horrific murders and that he fit the serial-killer profile as defined by the FBI today. He examines eyewitness testimony that placed Kozminski with one of the victims. He draws on a decade of his own research, including trips to Poland and England, to uncover Kozminski's past and details of the case, reveal his bizarre behavior, and build a strong circumstantial case against him. With a Foreword by former FBI profiler and pioneer sexual predator profiler Roy Hazelwood and featuring dozens of photographs, illustrations, and maps, Jack the Ripper and the Case for Scotland Yard's Prime Suspect presents the only realistic and convincing solution to the notorious mystery of Jack the Ripper.