According to modern science, the last will of murdered person is always to kill the murderer in self defence.
Homo Sapiens are wired through their neural network coprocessors in the brain grown from code in DNA passed to us from ancestors to posess self preservation instincts.
So if you scan the brain of any person being aware of them being murdered by a murderer, you will find out that they want to save their life at the cost of the murserer’s life. It is pretty well understood primitive biological function of the primal brain we all share.
It is only because the murderer did not gave the victim the chance to execute their self defence rights that we will setup a justice system and execute it in their name as retribution. We will mourn and more as restitution.
Such is the logic of reality, believe me ;]
Having said this, if you want to be like Jesus, you can forgive by default in all cases.