We are all murderers. Perhaps you have not yet murdered. Does this make you exempt? You may not have murdered, but have you been pressured to do so? Only when we are pushed to our limits do we reveal ourselves for who we really are.
Violence is very easy to understand. The ego feels it has a fundamental right to happiness, and will destroy anything that stands in its way. This may mean killing a mosquito - or a person. Yes, to kill even a mosquito out of anger reveals the mind of a murderer. So I say, where there is ego, and the hatred of suffering, there is violence.