Social media "vigilante" shot and killed by target

In the real world, all vigilantes are like the fake batmen at the beginning of the Dark Knight. The difference is the real world doesn’t have a real Batman. Please don’t take the law into your own hands. The amount of bad things that can happen (you getting hurt or killed, screwing up an actual criminal investigation, tipping off a bad guy and making them harder to prosecute, and worst of all, accusing an innocent person and ruining their life) overwhelmingly outweigh the good thing that can happen (bringing an actual predator to justice).