Dream about someone else killing someone indicates your attempts to save a part of yourself from being destroyed. Emotions that have been suppressed into your subconscious are becoming too overwhelming to keep inside any longer. You do not believe in your own ability to achieve your goals. It is a signal for a disturbance in your psyche and well-being. You lack leadership abilities.
Someone else killing someone dream is a message for someone who is excessively gullible or sentimental. You are being too theatrical or too melodramatic. You need to stop dwelling on your past emotions and clear them away. This expresses either a new beginning or an ending to a situation. You are lacking a sense of personal space.
If you dreamt about someone else killing someone:
You may try violently to stand your ground today, but why bother? It is worth it to actually take the opposing argument into account. You have an incredible opportunity in front of you in which you can grow and learn a great deal. Embrace it.