Riddle of the Golden River - Inspector Winwood Mysteries, #12

On his first day back after his holiday Detective Chief Inspector Steve Winwood gets the report of a dead body found on the bridge over the Rutter river. In the early hours of the next morning a body is thrown against the front doors of the Fleetwood Arms Hotel stabbed through the heart in the same way as the first victim. Things go from bad to worse as a third body is found crushed between the riverbank and a moored up houseboat.
The only connection is that all three have been similarly killed with a long, sharp blade which leads his newly appointed Chief Superintendent Diane Bliss to ask if there is a serial killer at loose. Steve is unable to confirm this one way or another but he is sure that he is not going to enjoy a new working relationship with his senior officer who starts by asking him to smarten himself up. The new Chief Constable is not so interested in dead bodies in Rutherford as to a fraud that has caught up senior police officers and minor politicians.
Despite Steve's protestations that this is a case for the Fraud Squad he is assigned the case and only given some bare clues as to the nature of the fraud which are three names; Peru, Alberto Pereira and Pactolus. The best clue he has is a memory stick from the second victim's possessions which he hands to Detective Sergeant Miles Davis, more at home with spreadsheets than himself. A search of the last victim's home brings forward a key to solving the riddle set by the Chief Constable.
Steve's mind is elsewhere. He is thinking about retirement. For the second time. The world has changed since he joined the force. His instinct tells him that the three dead bodies and the fraud case are connected. It is fortunate that he has no expertise in spreadsheets but Davis has, so between old fashioned policing and modern technology they solve both the riddle and the identity of the murderer.