Well consider this:
1. Person commiting crime once has more possibility of commiting a crime again.
On this notion, capital punishment. I am assuming we are just talking about crimes applicable for capital punishment.
2. Subhay ka bhula if return home then he/she is no more bhula, people do mistakes, repents/realizes and change themselves fo good. I know at what cost? but they do.
In this case life prison.
3. Brutality and circumstances of crime should be considered.
4. Ignore above three, someone kills another human ...give him capital punishment, but hello, who are we to decide life/death. Finally I made up my mind, give life imprisonment, anyway life will s* more being in prison all life then dieing.