Remember that employees are a valuable resource. Avoid obnoxious, self-righteous, threatening, or accusatory conduct that could damage the company's image in the eyes of employees. You will have to live with most of the people you question long after the investigation is over. Due Process Observing due process during the conduct of the investigation protects the company's image and reputation with its employees. A hard nosed investigation may win the battle by identifying the thief but may lose the war by alienating employees.
Due process means pushing employees to remember and tell all of the details of their story.
It means allowing them time for their memories to work and letting them correct and change their stories. You can keep track of the timing of each story and its changes as they develop. Allow the employees to examine any helpful or pertinent documents at some point during the investigation, but not necessarily up front. Be as honest with the employees as possible. The goal is to leave all affected employees with a feeling that the company has treated them with respect and has been careful, civilized, and fair.