This question was put to the forum members by one of the friends.
I replied thusly:
Vengeance cannot bring the closure. Even if you kill the entire family of your enemies, you carry enormous Karmic burden within and if you believe that Karma is a theory which might be true then there are bound to be repercussions and comeuppances in incarnations to follow which might seem final but would never be and it would be a really really long time after you find yourself free from this entangling 'eye for an eye' melodrama.
For a person like me who is fine without Karma being a rock-solid theory (Though I use it to discuss on many spiritual things.) there is a burden on psyche which comes with vengeance. Whether there is an after-life or not, whether there is another incarnation or not, the load and guilt borne out of having butchered someone or even having harmed someone because of the urge to take revenge is too much for me. It would be such a perturbation of my mind that I would not be able to live peacefully no matter how many meditations I try or how many poor people I feed to.
What then would bring a closure?
Forgiving brings closure in my opinion. In many cases you will observe that wicked perpetrators have their destiny set well in advance before they have even committed crime and they meet grave misfortune on their own. Though this might bring some satisfaction to the sufferer but it's not what actually brings the closure. Even slight remnants of ego that the perpetrator suffered because he had made me suffer brings further bondage and attachment to the subject in various other actions and consequences thereafter. The final closure is forgiving which should dissolve any stains from our conscience.
It's easier said than done but definitely many times better than 'eye for an eye' in my opinion. You observe than many movies and books publicize 'eye-for-an-eye'; though it's Karmic but I personally believe that Karmic retribution is nature's cycle and need not necessarily be exercised by someone who suffered. I feel that justice comes by its own means and in due time and it comes no matter whether the person who was injured is there to witness it or not.