Police Procedure & Investigation By Lee Lofland

To write a credible police story, writers need to know how police investigations really work.
This latest book in the Howdunit series gives the lowdown on how everyday folks, as well as writers and journalists, misunderstand or incorrectly portray how the police work. Keeping in mind the mistakes most often made, this guide provides insight into a cop's world: the terminology used by police officers; an in-depth look at the tools of the trade; legal terms; courtroom terminology; jail, gang, and convict slang; street talk; drug information; and tons of other useful information. Perfect for learning why and how cops do what they do, this book is the next best thing to having a police detective personally assigned to the reader.
http://www.writersdigestshop.com/howdunit-book-of-police-procedure-and-investigation-paperback