Any investigation must start somewhere, Desmond was not exactly a detective or investigator, but he still had some notions on the subject, mainly from the things he had learned from his father in the past, one has to remember that his father was for many years a military policeman of a special division and the investigation was his forte.
Unfortunately, Desmond had not inherited the detective skills of his father, of course, Desmond had a high intellect, sharp senses, and a great capacity for analysis but that was not all that he needed to be a great detective.
In the words of his own father, to be a great detective one had to understand how the people they investigated thought and felt, whether they were the victims or the criminals, understanding their motivations could be the final piece of the puzzle.
