Hare Krishna
The Vedas tell us that there are six kinds of aggressors: (1) a poison giver, (2) one who sets fire to the house, (3) one who attacks with deadly weapons, (4) one who plunders riches, (5) one who occupies anothers land, and (6) one who kidnaps a wife. Such aggressors are at once to be killed, and no sin is incurred by killing such aggressors.
The explanation why is this killing of an aggressor good is - you kill one man, an aggressor, and then others who would like to do the same mischief will be restrained to do the same mischief. Thus killing of the six types of aggressors have rectifying effect of criminal mentality. Nowadays of course this is not followed because of humanstic feelings and people are just put into the jail where usually they have very nice time. In some countries the jails are like hotels. There is a TV in each prison, special diets if required, playgrounds etc. Some criminals commit again and again some mischief because they like nice prison life. But what is even worst, the free criminals who are not in the jail are not discouraged but rather encouraged to do mischief. Anyway, the good purpose of killing few people is therefor, that you get peace in the society. And of course, If you could get all the people to chant any of the holy names of God like Allah, Jehova, Hare Krishna or whatever then all traces of criminal mentality would disappear. IOW a religious men develops all good qualities including non-violence, compassion and mercy to everybody. So, how he/she would commit any criminal activity?
Please chant Hare Krishna and be happy
Nitai