At many firms, the model employee comes in early, leaves late, and never takes the maximum allotted sick and vacation time. Unfortunately, some of those who seem dedicated to their desk are thieves; they can’t leave, because then someone will find out about their sham bank accounts, vendor kickbacks, or phantom expense reports.

Research of frauds committed in 2004 by the Association of Certified Fraud Examiners shows that those who commit fraud look loyal. Nearly 70 percent of them are employees rather than managers, and over 73 percent of them have worked for the company for more than three years.