De book is an abject failure in that it fails totally to uphold the first principle of investigative writing and that is to keep all options open in an unsolved case.
It is a book written to reflect the time of 2015 when against all the odds Madeleine McCann's case has been reopened by the authorities in Portugal and here.
The book written eight years ago reflects that time. It unfortunately highlights an investigation which failed to uphold the principles you consider important in investigative journalism and which I consider paramount in policing and that is to keep all options open.
The theory was followed ... not the evidence. The chief investigator saw everything through the prism of his own prejudices and experience ... both seriously flawed.
That Summers and Swan are even handed authors is reflected in the slight manner in which this incompetence is reported ... I wonder if they now in retrospect regret not actually doing the hatchet job they could have.