In a country like mine,taking laws into your hand can be beneficial because the police are not effective and can't be trusted.
A criminal who ought to serve some jail term and make some new friends in prison may be released if he knows the right people. The honest truth is that corruption has eaten deep into the fabric of the police force and they can't be trusted with criminals.That's why people kill criminals (thieves,rapists ) and so on without taking them to the police.
They also lean towards the believe that the kind of punishment meted out to this criminals does not sometimes commensurate with their offense.
I don't believe in jungle justice. It is an archaic practice and in a sane country where everything works,criminals are supposed to be handed over to the police,charged to court and be locked behind bars but unfortunately, nothing works in my country. That's the main reason people initiate jungle justice. At least,they have one less criminal to worry about