One thing about writing crime – you need to do a lot of research! In addition to my standard stock of books and the experts I consult, I also do specific research for each book. In the case of The Killing Hands, this focused mostly on organised crime, gangs, Kung Fu and contract killers. Below is pretty much every specific resource I used.
Other law enforcement
Hitman Manual for Independent Contractors
Louis Schlesigner, The Contract Murderer: Patterns, Characteristics and Dynamics, J Forensic Sci 2001;46(5):1119–1123.
General forensic psychology
Organized crime and gangs
The Ancient Art of Life and Death: The Book of Dim Mak, A. Flane Walker & Richard C Bauer, Paladin Press, Boulder, Colorado, 2002
Death Touch: The Science