Situations arise when third party confirmation and review is required for a transaction or group of transactions. These situations sometime necessitate setting up an inquiry to investigate the facts. When for a special purpose an inquiry is made into the accounts of the business it is called investigation. Investigation involves inquiry into facts behind the books and accounts, into the technical, financial, and economic position of the business or organization.

Investigation is an examination of books and records preliminary of financing or for any specified purpose, sometimes differing in scope from the ordinary audit. Investigation implies an examination of and records for some special purpose.