I remember what that movie A Time To Kill is about but I forget the details. If there was a system in place protecting someone who raped and killed a child, trying to protect that person's reputation or simply because they are racist and see another person or child as unworthy of justice, then the rapist/killer would be free to do it again. Then I have to say that would be a time to seek vigilante justice.
But think about the case of Ahmaud Arbery's murder. Vigilantes pretty much made a false accusation, tried to make a citizen's arrest, held him at gun point as a captive, then killed him. A prosecutor refused to charge the men and she now faces charges too. And in the court room, the defendant's lawyer tried to get the jury to be more red neck. They even demonized Arbery's body saying he had dirty toenails as a reference to a slave. What if the system all got away with their obstruction and let those three men free? Would that be a time to kill? Should we discriminate and kill for a child but nor for a grown man???
If they get away with it, and the system gets away with it, then that issue becomes widespread and just plain corrupt. We need the system to be able to do its job and hold criminals accountable. If that fails, and the problem becomes larger, then what happens is a revolt. People will take justice in their own hands. Because that ends up being a threat to everyone who looks like that particular victim. This also can become a double edged sword if vigilantes take matters in their own hands because who is to say who is right? Rittenhouse went on a premeditated killing spree and others think he was a good vigilante for it.
This also reminds me of the movie Braveheart where Wallace's secret wife was murdered in public for everyone to see. Imagine living under another's rule and having to share your wife to give her virginity to a tyrant? Wallace then revolts and the others revolt with him and kill the bastards. Usually a victim whose justice goes unanswered is a symptom of bigger problems. You may have vengeance in your heart for that one victim or a few victims, but look at the bigger picture of a failed system, and fucking revolt!!!!!!!!!!!!!!!! Kill the tyrants!!!!!! Just don't be a fake Rittenhouse vigilante where a corrupt judge let him free. Should the victim's parents or siblings seek vigilante justice, since the system failed them? Then what. What happens is two sides always thinking they are right and more and more people get killed.
It's hard to answer that question because everyone is more sympathetic to the child and not to a grown man, even if both needs that justice. And if you are on the side of the minority, like in that movie A Time To Kill, and you seek your own justice, think about what happens next in that oppressive system. The oppressors will want revenge for the white man and kill innocent blacks who had nothing to do with it. Then they are forced into a revolt. That's how things work. On and on and on. There are always oppressors and the oppressed. Something like that child's murder shouldn't go unanswered. And what is probably even more affective than taking matters into your own hands is to get the whole community involved. If they get gunned down, then war it is. Or riots.
We have seen modern day systemic oppression at work, or a modern day genocide of blacks by the police. And do they seek their own vigilante justice? They did what angry people do, who feels helpless, is riot. And that got attention. Did it change anything? Nope. But it did get public opinion and awareness. We now know the police need serious reform. And if the oppression of blacks and browns goes unanswered. Next time it will be more than a riot. That's just how things work when people can no longer take it. They revolt.
And that is completely different from being a bunch of nazi fascists who try to overthrow an election. They are lying about a stolen election. Much different from blacks getting murdered by police and seeking justice and equality. Being a vigilante goes both ways, even the bad people and oppressors falsely seek justice. More like they use violence to scare people into oppression. That is the tactic for authoritarians. They will always play the victim, always use brutal force, always get you before you get them mentality, always protecting the system of oppression, label you a terrorist if you stand up, arrest you if you speak out, brutalize and kill you for protesting, take away your rights, all so they can abuse you and do things like rape and kill children because they believe they have the privilege to do it.
Best thing I can say, is seek support from the public. Demand justice. Protest. Riot. Then revolt.