I haven't read this book so can't comment on that. However I do remember that there was a young woman murdered in Preston, Lancashire at the time of the Yorkshire Ripper murders. I believe that one of the letters or phone calls that the Police thought at the time came from the Ripper counted another murder in and the Preston murder had similarities with the Ripper murders. However Peter Sutcliffe was never tried with this murder and it has remained unsolved. My personal view was that this was a 'copycat' killing, possibly by the hoaxer contacting the police. So who knows, there may well be other 'Ripper' murderers out there yet.