Simon Coffey & Dennis G. Fitzgerald 
Informants, Cooperating Witnesses, and Undercover Investigations [PDF ebook] 
A Practical Guide to Law, Policy, and Procedure, Second Edition

This book covers every aspect of the informant and cooperating witness dynamic a controversial technique shrouded in secrecy and widely misunderstood. Quoted routinely in countless newspaper and magazine articles, the first edition was the go-to guide for practical, effective guidance on this tricky yet powerful tactic. Extensively updated, topics in this second edition include changes in the FBI’s informant program, changes brought on by immigration reforms, recent high-profile cases, and the changing nature of compensation and cooperation fees. It also examines the management of informant-driven search warrants and challenges posed by fabricated information.