To dream that you have been assassinated represents a hopeless situation that needs your immediate attention and action.
To dream that you are a witness to an assassination indicates that you need to pay more attention to some small detail. Do not overlook the seemingly insignificant things in life. In particular, to dream that an important political figure is assassinated on your watch implies that you are lacking support in your waking life. You feel you are alone in your views and decisions.
To dream that you are an assassin implies that you are trying to kill an aspect of yourself. Perhaps you are trying to put an end to a habit or relationship. Consider the characteristics of the person you are trying to assassinate and how these qualities relate to you.