Generally I would so 'no', citizens should not take matters in their own hand. Exceptions are when there are immediate and severe dangers for lives of people. Exceptions are also when people are caught red-handed and citizens hold someone until the police arrives. In case the monopoly of the state to exercise control and power is not strictly observed the danger can be great. Who decides what 'law and order' means. Not so long it would have been a law and order issues when a non-While would have gone to a place reserved for white. This was in Apartheid South Africa and also the USP. Other examples are abundant.
Certainly 'no', citizens have no right to take matters into their own hands but rather enforce the right measures are taken by following the rules and laws that stipulate the functions of the local government. Although, citizens have the right to register their displeasure to the unwillingness of local government to enforce law and order they cannot take matters into their own hands. Once citizens take matters into their own hands that I would say there is a breach of law and also disregard for local authorities which could lead to prosecution.