1. Decide whether to investigate. Before you put on your detective's hat, take some time to decide whether you really need an investigation. In a few situations -- for example, if all employees agree on what happened or the problem appears to be minor -- you may reasonably decide that a full-blown investigation is unnecessary. Usually, however, it's best to err on the side of conducting an investigation. If the problem is more serious than it seemed, failing to investigate can lead to legal trouble -- and continuing workplace problems. And sometimes, you just can't tell how widespread or substantial a problem is until you do a little poking around. 2. Take immediate action, if necessary. You might have to act right away -- even before you begin your investigation -- if a situation is volatile or could otherwise cause immediate harm to your business. If an employee is accused of sexually assaulting a coworker, stealing valuable trade secrets, or bringing a weapon to work...