Recommend several teaching materials: criminal (or criminal) investigation, criminal technology, crime scene investigation, forensic medicine. If you want to extend it a little further, look: criminal psychology, investigation. Dr Li Changyu's crime scene investigation manual.
Books dealing with people:
Carnegie's "The Weakness of Human Nature", the black book, the classic of the old fox.
Five Minutes of Touching the Heart —— Giant Yuan Hua
You must know the gender.-Dale. Carnegie
"Popularity"-Xiaoyun
There are black forces in Hong Kong. Hong Kong is known as a free port, and the underworld forces are very serious:
Major underworld organizations and activities, major underworld organizations: According to the estimation of the Hong Kong police, there are currently 50 underworld organizations in Hong Kong, of which 15-20 is relatively active, with more than 200,000 people, and about 10000 people actually engage in criminal activities.
The answer is to handle the case, the answer from Suzhou Liang lawyer.