(1) Notify your friends and relatives of what has happened.
Do not be vague. Name names, and specify dates and circumstances. Identify witnesses if possible and provide supporting documentation if any is available.
(2) Inform the police. The police will do nothing with this
information except to keep it on file, since they are powerless to act until a crime has been committed. Unfortunately, that often is usually too late for the
victim. Nevertheless, place the information in their hands.
Obviously, if you are assaulted or threatened before witnesses, you can get a restraining order, but those are palliative at best.
(3) Make sure that several of your friends have the information in the event something happens to you. That way, an appropriate investigation will follow if you are harmed.
Don't tell other people who has the information, because then
something bad could happen to them as well. Instruct friends to take such an incident to the newspapers and other media.
If you are dealing with someone who has considerable money, you must realize that they probably won't try to harm you themselves, they will contract with someone to make the hit.