It's just not fair
It started with the end of the world, before it got worse. Not the literal end of the world, of course, but when your son, your only child, the only thing you have left after your wife died a few years ago, is murdered, well, it certainly seems like the end of the world. You're a good man, though, so you have faith that although you will never see him again, or get to go to his wedding, or spoil his children at Christmas, at least the forces of justice will be brought to bear on those responsible, and a dangerous element of society will be removed. You wait, and time passes, and nothing happens. You head to the police station, track down the officers in charge of the investigation, and make some inquiries. They are polite, and sympathetic, but they have nothing for you. This goes on for a while, and goes through several stages. First, you believe them. They're busy men and women, doing their best to protect society. Then, you start to think that they're incompetent, or lazy, and start doing a little investigating on your own. You don't have enough money to hire a professional detective, but you've seen movies and read books, you know how to ask people questions. It's slow at first, but you start building up a picture... and you're horrified. It turns out that the police weren't incompetent. They had found out who was responsible... and couldn't do a single thing about it. As it turns out, the man responsible for the life of your dear son ending is a powerful, influential man. Corrupt and wealthy, he has ties to many of the major businesses in the city, more of the smaller ones, and countless street-level operations, as well as friends and "friends" at all tiers of the city's political infrastructure. He is, quite simply, untouchable by the system. He is also specifically responsible for your son's death. What can you do?
You sell most of your possessions. You move to a new apartment. You spend a lot of time on the roof, just watching the people go by on the streets below. Finally, the waiting period on your rifle ends, and one calm sunny day, you snipe the man. You don't run, or make excuses, when the police finally check the roof. You are sitting at least ten feet away from your rifle, with your hands clearly visible. They arrest you, take your story, and proceed to charge you. You plead guilty, and dispute any attempts by well-meaning citizens or groups who try to make you a hero for killing a monster, and try to get your sentence reduced. You are, in fact, quite vocal that you should be put to death. You murdered a man, with malice aforethought, and there are consequences for that. It doesn't matter who you are, or who you killed... there must be consequences.
You sell most of your possessions. You move to a new apartment. You spend a lot of time on the roof, just watching the people go by on the streets below. Finally, the waiting period on your rifle ends, and one calm sunny day, you snipe the man. You don't run, or make excuses, when the police finally check the roof. You are sitting at least ten feet away from your rifle, with your hands clearly visible. They arrest you, take your story, and proceed to charge you. You plead guilty, and dispute any attempts by well-meaning citizens or groups who try to make you a hero for killing a monster, and try to get your sentence reduced. You are, in fact, quite vocal that you should be put to death. You murdered a man, with malice aforethought, and there are consequences for that. It doesn't matter who you are, or who you killed... there must be consequences.