The Diary Of A Murderer

The detective Eve Davenport received strangers letters from a murderer.
The murderer is a professionnal that why he or she named "The Invisible Murderer" because there's no hints on the scene of crime, no DNA and no fingerprint. Eve investigated on this murderer for more than two years. The victims are all killed the same way, discovered by a member of their families, out of armchair, the legs jutting very stiffly at a strange angle, an arm protrivided as well and they are all be a part of family Mackinlay, d'Almaine and Ure.
The detective received after discovering the corpse a page of the diary of the murderer, he or she narrated a journey when he or she was a kid.