Somewhere along the way long after the investigation is complete, the question will be raised regarding who was interviewed and why. Like a television crime show, questions will surface about mysterious witnesses who were not questioned. Obviously, hindsight helps to bring clarity. One of the most important jobs of an investigator after finding the facts is to be able to explain why he did what he did at all points in the investigation. In other words, why were certain individuals selected to be interviewed and others were not? The interviewed should always ask, “who should I speak with that knows more about….?” Always ask who can corroborate statements that the witness has made. The interviewer should avoid cutting corners because he/she thinks a witness is trustworthy or that another lacks credibility. Seek not only to corroborate but also to disprove statements or claims made. In addition, be sure to review and understand documentation which can help corroborate statements or claims made. If documentary evidence is technical in nature, the investigator will need to demonstrate that he/she understands it?
For more, see my book: Workplace Investigations: Discrimination & Harassment