Joseph Fletcher based his ethical theory of Situation Ethics on the teaching of love in the bible. The word used is agapé love which is selfless and caring love not romantic and selfish. Fletcher said that the moral thing to do in a situation is what you believe shows the most agapé love. What you do should be based on the situation and there are no set rules.
A situation ethicist would say that killing somebody would show no agapé love however it does affect the rest of the world. If a murderer is killed then no one else will get killed by that same murderer so it is showing care to other people in the world. If the murderer only killed someone as self defence it would be wrong to kill them as you are not giving them a chance to redeem themselves and it was not their fault they had to do what they could to stay alive. However situation ethics is open and people have different opinions on what is loving or not. If you are always careful that your motivation is pure and always try to be loving it will be moral.
A situation ethicist would say that killing somebody would show no agapé love however it does affect the rest of the world. If a murderer is killed then no one else will get killed by that same murderer so it is showing care to other people in the world. If the murderer only killed someone as self defence it would be wrong to kill them as you are not giving them a chance to redeem themselves and it was not their fault they had to do what they could to stay alive. However situation ethics is open and people have different opinions on what is loving or not. If you are always careful that your motivation is pure and always try to be loving it will be moral.