We Never Know
No Slack
No, to put them in jail is the best option, because if we kill them they will not learn. if they must sit in jail for 50-60 years they would understand that what they did was really wrong. And they knew they would not be free because of what they did.
Put them in jail where they will be a financial burden for 50/60 years and will never have to pay for anything else during that time.
That means family members and friends of the innocent victim that was murdered help pay for his free room/board, free meals, free medical, free dental, etc. with their taxes.
Where is the justice in that?