Once again the inextricable links between drug dealing, poverty, troubled family lives and a disrupted education have been laid bare with the conviction last week of 19-year-old Ayoub Majdouline for the murder of Jaden Moodie, 14.

Both Majdouline and Moodie had been involved in drug dealing, including “county lines”; both were members of rival London territorial drug-selling gangs; both their fathers had respectively been murdered and deported in the context of selling drugs. Majdouline had been repeatedly abused as a child and eventually went missing from foster care, while Moodie’s family had felt compelled to move from Nottingham to London in the face of threats from local gangs.

As in the case of Corey Junior “CJ” Davis, another 14-year-old murdered in London, Moodie’s family say they had repeatedly sought the help of public services. As with Davis, it seems they were unable to transform his circumstances in the face of competition from gangs, and it is reported that Moodie was excluded from schools in both Nottingham and London.

Both Moodie and Majdouline were expendable pawns on the frontline of the global illicit drugs trade and may well have been replaced by other vulnerable boys or young men within days if not hours of the attack in January. The challenge confronting police and policymakers tasked with addressing violence is to do so while the potential for illicit profits persists, creating the conditions in which youngsters like Moodie are vulnerable to lifestyles most of us can barely imagine.

For users, drugs like heroin and crack can be a way of coping with emotional trauma and other adversity. For those involved in dealing, however, they can be a source of income, status, companionship and identity, including when legitimate opportunities are limited by the likes of poor education, disrupted family lives and social exclusion.

Facebook Twitter Pinterest Ayoub Majdouline, who was found guilty at the Old Bailey of the “cowardly and shocking” gang murder of Jaden Moodie. Photograph: Metropolitan Police/PA

The profits generated by drug dealing are visible in communities, as are opportunities to get involved, willingly or otherwise. Particularly in the case of crack and heroin, dealing tends to be local and comparatively conspicuous, serving a relatively small but profitable group of users, with the most exposed dealing roles – such as delivering drugs and collecting cash – typically occupied by teenage boys and young men (and sometimes dependent drug users). They may be recruited through promises of cash today and future wealth, groomed through acts of apparent kindness and generosity that exploit their social isolation, poverty and neglect, or compelled to act through coercion.

The latter may include the creation of debts that must be settled by undertaking criminal tasks, for example being given “free” drugs that must then be repaid by dealing. Threats of violence may be made against family members.

Whatever the means, vulnerabilities are created or exploited by more senior criminals looking to offset risks on to others while maximising their profits, and those selling the likes of crack and heroin at street level are generally expendable and often earn very little. A police officer experienced in operations against crack and heroin dealing in London once memorably told me he had “never searched a drug dealer who was wearing clean clothes”, while the descriptions of youths returning home from periods spent away selling drugs for ‘county lines’ often refer to how dirty, exhausted and underfed they are.

Drug dealers are in turn preyed upon by other criminals, partly because they are unlikely to call 999 if robbed, and accordingly arm themselves for protection; both Majdouline and Moodie had previously been caught carrying weapons. Furthermore, many sales are conducted on credit (“on tick”), and in the absence of recourse to the law to recover unpaid debts, especially where trust is weak, drug-selling groups rely on violence or the threat of violence to underwrite their businesses.

Facebook Twitter Pinterest Jaden Moodie’s sister, Leah Moodie-Green, speaking at a memorial for Jaden in Arnott Park in Nottingham. Photograph: Fabio de Paola/The Guardian

Indeed, a key imperative for those selling drugs is to have a reputation as “not to be messed with” to avoid unpaid debts, rival groups taking market share, and the risks of being “grassed” to police. Often this is built through overt and grievous acts of violence. That reputation may nevertheless be threatened in social settings such as parties or on social media, where perceived acts of disrespect or direct threats in front of social audiences may challenge criminal as well as social status and require a reaction, with the general preference being for direct retaliation. Where group or gang dynamics are involved, collective responsibility and revenge may mean other gang members being targeted.

Illegal drugs markets are, in effect, a “golden thread” running through many accounts of violence in London and elsewhere, whether involving knives, guns, gangs or exploitation (each variously the focus of government policy to tackle violence over the last two decades).

While Moodie’s family have some kind of justice and Majdouline faces a life sentence (the police continue to seek his four accomplices), it seems unlikely that the fate of either victim or perpetrator in this case will change much on the streets of London and Nottingham.