Employee thefts are either personally or environmentally induced and are sometimes a combination of both. Personal inducements can be classified as (1) economic (employee perception of need or desire for more money), (2) ideological (spite, hate, or anger against the victim), (3) egocentric (proof of cleverness and knowledge), and (4) psychotic (distorted sense of reality). Environment inducements which provide the opportunities for theft include inadequacies in internal accounting controls; inadequate access control to computers, terminals and other information, telecommunication and data processing equipment or facilities; reward system; ethical climate; and climate for interpersonal trust. Means of effecting a computer-related theft involve exploitation of weaknesses in controls, personnel, and technology. Methods of computer-related theft are 'input scams,' which involve the creation of a false or faked debit; 'throughput scams,' which consist of manipulating data while running through the computer rather than before the run; and 'output scams,' which involve the criminal use or destruction of computer outputs. Implications of the proposed classification system for prevention systems are discussed, and an internal theft prevention system is graphically portrayed.