If you kill someone in your dream, the dream means that you are trying to escape from that influence probably exerted by another person.
killing in a dream is a sign of offering. Killing dreams are most of the time not a good sign, because the killing can represent mental conflicts.
If you witness a killing in your dream, this could portend the death of a loved one. Killing a helpless person portends grief and failure ahead. Killing someone means that you might suffer because of your own negligence, which may bring you humiliation and worries.
If the killing was done in self-defense, a better position, and either social or at work, is possible. Killing in dreams symbolizes your need for power.