The 'co-author' of this book is Christopher Berry-Dee, who seems to be incapable of not bragging about his previous journalistic and investigative work in the field of serial killers, while the actual work he created is a really bad piece. You can't even really say that someone has written a book, it more seems like a compilation of facts with some drops of possible truth in it.
As many have said - the book is not written by Aileen herself.