The factors causing fraudulent behaviour were best described by Fraud Triangle of Donald R. Cressey and Edwin Sutherland. For years, academicians and practitioners used fraud triangle for fraud deterrence -to show which factors should be removed. These were incentive or pressure, opportunity and rationalisation. The fourth factor, capability, is added by David T. Wolfe and Dana R. Hermanson and redefined the fraud triangle concept as ‘Fraud Diamond’ in their article published in CPA Journal in December 2004. Please see the link for the full article.