What is the ruling on hiring thugs to assault a harmful young man who threatens girls to extort money from them, in a state of security breakdown?

Originally, it is permissible to hire someone to protect lives, honor, and property, and to prevent aggression against them. However, hiring someone to assault a criminal, take revenge on them, or punish them is forbidden; because it leads to chaos and allows criminals and wealthy individuals to control society. If there are special cases that can be dealt with in this manner without greater harm or corruption, and without an increase in aggression, then such cases require a specific fatwa from a scholar knowledgeable of the circumstances and details, in order to weigh the benefits against the harms.