Vigilantism and revenge are often two sides of the same coin. If people were just rounding up criminals and peacefully providing them to the police for justice

Vigilantism and revenge are often two sides of the same coin. If people were just rounding up criminals and peacefully providing them to the police for justice along with evidence and testimony then it wouldn't be vigilantism. Vigilantism is essentially just retributive justice without the benefit of due process.