The Criminal Justice System (CJS) has been instrumental in the crime prevention efforts in most urban societies. Yet the CJS alone may not be sufficient in the provision of adequate security and safety in urban societies. There is therefore the recognition that addressing crime and insecurity in urban areas require an integrated crime prevention strategy that takes into cognizance the institutional, social and spatial/geographical causes of crime within specific urban context. More so, it has been argued that the design of any crime prevention policy, although should be context specific and culturally relevant, should also be formulated within comprehensive city planning systems. Based on this understanding, the paper reviews some of the approaches to effective crime prevention in urban settings and examines their relevance and applicability to the Ghanaian urban setting and experience. This is very important, particularly when recent studies in Ghana have shown variations in the nature, type and prevalence of crime and insecurity in and across cities in Ghana. The paper concludes that for effective crime prevention in urban Ghana, there should be coordination among formal, informal and planning institutions in the design process as well as implementation of city plans since crime is becoming more complex and sophisticated.

Since the 2010 post-electoral crisis, the municipality of Abobo has experienced a new form of violence that involves gangs of ultra-violent young people known as "microbes". Like the microbes which are characterized by their small size and great ability to harm human health, these gangs have exploited the weaknesses of the urban governance and security, and the precariousness of Abobo's socio-economic environment to take root.

Our study reveals a strong link between young people's involvement in violence and poverty in the Abobo areas. In fact, those who engage in various forms of violence (firearm, clubs, machete attacks) usually come from households where the head of the family is unemployed or has a low income. In the districts, food security is not always guaranteed and not all young people benefit from school education. Consequently, left to fend for themselves parental control is considerably weakening and violence is the only source of survival.

The microbes benefit again from the poor urban planning (problem of street lighting and uncontrolled occupation of the roads by informal activities) to trifle with the police force and rob, stab or murder passers-by. It is hope that the Security Sector Reform which aims to strengthen the capacities of the police force, train and re-socialize "microbes" in several technical centres across the country will help restore security.

It is, however, argued here that these strategies can only be successful if the original socioeconomic factors and management constraints circumstances of these delinquent young people are first taken into account.

Vigilantism and crime are assumed to be intimately tied by a causal-effect relationship, the first being usually presented as an answer (legitimate or not) to the second. In this paper I postulate two things: firstly, that crime and vigilantism are the two faces of the same medal in this sense that they are both rooted in the marginalization of the youth. Therefore, that secondly, given such a social, economic and political ostracism, vigilantism including mob justice and the crime it pretends to eradicate are two diverging answers to the same problem. They are the two modalities of action through which the most excluded young people of each neighborhood try to reconstitute themselves as full social actors and to influence community's affairs.The argument of this paper rests partly on a fieldwork observations and interviews with a ten of young denizens of the city I made during a one month journey in Lagos in January 2016 and on secondary data; specifically it reconsiders and comments vigilantes groups studies made in Nigeria during the two last decades and demonstrates that the involvement of the youth in such groups obeys to the same motivational dynamics at work in criminal activities, that is, the search for incomes, for social recognition, for mates and family members' respect and so on. A close analysis of the Area Boys a notorious group operating in the city of Lagos since the early 1980s even shows that some of these groups of young people often behave interchangeably as criminals and as vigilantes.

Since 1976, Mozambique was plagued by an internal war that would last for sixteen years.

Devastating and violent, it has spread to the whole territory and has also affected the population in an unequal general way, disintegrating Mozambican society in an unprecedented way.

Conflict resolution techniques applied to the Mozambican civil war have implemented programs for the reintegration of ex-combatants into society (DDR), involving children and young people too, who had been combatants in the civil war and also mechanisms of transitional justice, which in Mozambique resulted in a general amnesty.

The general amnesty would lead to some discomfort in Mozambican society by not allowing people to be confronted with the crimes they committed during the war. Traditional rituals involving ex-combatants (purification rituals [kuhlapsa] and exorcism rituals [kufemba]) have sought to address this problem at the host community level, as well as to solve the shortcomings of DDR programs.

Mozambique has shown that the reintegration of ex-combatants, especially the child soldiers, is an issue where peacebuilding can work side by side with informal justice techniques.

The cultural factor is at the heart of this intersection which shapes the attitudes of the parts in conflict and consequently can help them to overcome the trauma, enable social reconciliation, and prevent them from slipping sooner or later into armed criminality.

It is therefore in the interest of the DDR programs to include the involvement of local actors, who can help find creative and appropriate solutions for each case.

Les rapports entre conflits armées, expéditions militaires, trafic d'armes, rébellion et drogues sont aussi anciens que l'utilisation par les hommes des substances qui modifient leurs états de conscience. Ce contexte d'insécurité créé et qui a prévalu depuis le début d'un des plus vieux conflits du continent africain a non seulement découragé toute initiative économique en Casamance mais l'a aggravé et hypothéqué l'avenir de générations de jeunes casamançais par la démocratisation et la banalisation de l'usage de substances tant psychoactives qu'illicites.

Cette recherche empirique d'une ampleur jamais égalée entend creuser le lien entre consommation de la drogue chez les jeunes, développement en lien avec le conflit casamançais afin de mettre à la disposition des acteurs œuvrant pour le retour de la paix définitive, une base de données fiable.

L'Afrique ne dispose toujours que de très peu d'informations systématiques sur l'ampleur de laconsommation de drogues, ou sur les caractéristiques ou tendances de cette consommation.

Cependant, les seules estimations disponibles indiquent une forte prévalence de l'usage de cannabis dans cette région(7,5 %, soit près du double de la moyenne mondiale), tout particulièrement en Afrique de l'Ouest.

Cette communication a pour ambition de changer la donne et se fixe comme objectif d'aller en profondeur et de poser les jalons d'une longue et fructueuse réflexion sur cette question géostratégique qui touche aussi bien le monde urbain que le monde rural casamançais voire ouest-africain.