Book excerpt: Aimed at the busy professional who aspires to become certified in the field, Criminal Investigation for the Professional Investigator details essential techniques a trained investigator will be called upon to perform during the course of a career. The book is authored by a veteran of the NYPD who went on to launch and operate two successful private investigation agencies. It covers crime scenes, death investigations, the art of interrogation, and specific criminal investigations. It also provides important strategies for making arrests and testifying in courtrooms, details the most effective investigative tools to use, and explains the role of criminal defense investigators.