One of the most terrifying things that can happen to you as an employee is to find yourself in possession of information that reveals serious wrongdoing by someone of higher rank in the organization. No matter what you do with the information you may lose your job, but you could be emotionally scarred as well if you are not prepared. Even if you are prepared, you may not have a happy outcome. It might be only bearable at best.
I have been in this situation twice and have known several others who have found themselves involuntarily forced into becoming whistleblowers. It is not a situation one cares to repeat, but there are some things you should know which may help you survive with your sanity and dignity intact. By the way, we were all fired, for reasons which will become obvious.
By executive wrongdoing, I mean every serious off-policy and illegal activity you can imagine. These include: drug use, extreme sexual harassment, theft, cooking the books, insider trading, industrial espionage, falsifying sales records, diversion of money, falsifying time sheets, etc. The list is practically endless and many of the companies I worked for had at least one incident occur in the executive ranks while I was there. Fortunately, I was directly involved in the discovery of only two of these. Others blew the whistle on the rest.
First, let us see why such wrongdoing exists in the first place. There is generally a climate which fosters or is tolerant of wrongdoing by executives. If the person has been doing this wrongdoing for a few months, those higher in the organization are deliberately ignoring it for some reason. They may be afraid to talk or they may be involved in some wrongdoing of their own.
Your discovery of this information puts you in an extremely difficult position. You generally have no one you can turn to. If you confront the wrongdoer directly, you will almost always be fired for any number of false reasons.
Human Resources, contrary to your expectations, is not your friend. HR is there to protect the company and its executives against employees like you. They may give you an audience, but they will generally take no action against the offending executive. Instead, they will probably put you on report for trumped up charges of failing to do your job properly and may recommend your dismissal.
Getting a lawyer generally does not help, because you probably signed an agreement when you were hired that allowed your employer to dismiss you at any time for cause or for no cause.
Perhaps you decide to compromise your integrity, and say nothing about this to anyone at work. The resulting self-degradation will eat at you until you become ill or until you can no longer stand yourself. At this point, your work will suffer and you become a candidate for disciplinary action and dismissal unless you have already quit in disgust.
So, what can you do to come out of this with your sanity and reputation intact?
If you have understood what I have said so far, you will realize leaving this organization under your own steam is your only option. Yes, you can report the wrongdoer, but you should do it only after you have secured employment in another company or in another division of the same company, preferably with someone who detests the executive who is doing wrong and getting away with it.
Why should you leave this organization you have put so many years into? Look around you! You are in an organization that validates bad behavior by executives. What chance do you have for advancement? Go someplace where you have a chance to start anew. Once you start making waves, you will lose any chance for good references. Leave while you can and use your new experience to make sure that your new company is a more ethical place.
One more point. Keep your findings to yourself and do not share them with co-workers. You are likely to find that they do not want to hear about them. They recognize you as a lightning rod that is already buzzing with a corona discharge and will withdraw from you at the first opportunity. They may even report you to protect themselves. Once you are tagged as a whistleblower, anyone associating with you is putting their careers at risk.
So, in conclusion, you may not have asked for this opportunity, but you have inherited it nonetheless, so make the best of it. Get a new job before the roof caves in on those who misbehave and those who allow such behavior. You have just discovered that your company or division is infested with cockroaches and management likes it!
Move out smartly and consider yourself fortunate. Good luck.