I saw that a manager was embezzling and taking bribes. He was also sexually harassing his male employees, and giving the better jobs to his " buddies". I referred my concern to the HR department. Although this was supposed to be confidential, the manager was immediately told that I had done this. He made up a lie about me and got me fired.
Eighteen months later the company found all my allegations were not unfounded and removed him from posts of responsibility.
Although I never received any acknowledgement for blowing the whistle, the company has gone out of business and I am still looking for a good job, which I understand may be available.