The approach, introduced in 1970, features a seventh basic investigative tool in addition to the six age-old techniques used by criminal investigators. If properly applied, it can greatly enhance investigation of cases in which illegal profit and greed are the primary motives-- cases that otherwise would be deferred to the Internal Revenue Service or even dropped. Information about a suspect's financial transactions can also prove useful to solving other cases. Topics covered in this handbook include the net-worth-expenditures principle--what it means, and how it can be used in investigations. Also, there are practical exercises covering various possibilities, and a discussion of certain sources of information: records of banks, stockbrokers, travelers cheques, and major credit cards. 21 illustrations