An arms dealer in Jos. Photograph by Ruth McDowall. More photographs.

Last month, Nigeria became the first African country to sign and ratify the United Nations Arms Trade Treaty, a new international agreement designed to prevent the illicit trade of arms across international borders. The treaty has been hailed as an important step toward reducing violence in conflict zones, but little attention has been paid to what the treaty explicitly avoids covering: the making and selling of arms within countries.

Religious and ethnic violence has killed thousands of people in the Middle Belt, Nigeria’s culturally diverse central strip, over the past decade—and, in recent years, that violence has spawned an informal arms industry in the region, producing everything from guns to bombs. Almost five thousand illicit guns exist in the Middle Belt state of Plateau alone, according to Nigeria’s Committee on the Control of Small Arms and Light Weapons, a government advisory group. About thirty-five hundred of the guns are AK-47s made in France and the Ukraine and smuggled to Plateau State. But the rest, about fifteen hundred, are locally made.

In November of 2012, I went to Jos, the capital of Plateau, where I met Mmemme, a twenty-four-year-old Christian in a newsboy cap who happened to sell guns for a living. On Christmas Eve, 2010, the Islamist terrorist group Boko Haram had orchestrated deadly blasts in Mmemme’s neighborhood, Gada Bui. Later, he noticed some young men with guns patrolling the area, and he asked where they had gotten them. One of the boys took him to a local workshop where the guns were made; a year later, Mmemme had become a gun trader himself—to help guard his neighborhood, he said, and to make some extra income.

Mmemme started buying gun parts in a market and from local welders. He used to go once a week to the workshop, where a small group of men assembles the guns, but these days he focusses on selling the arms. To get one, people first pay him a deposit, which he uses to buy the materials. He sells each gun for between five and fifteen thousand Nigerian naira (between thirty and ninety-one dollars), at a profit of one to three thousand naira (six to eighteen dollars).

“We will sell to anyone who needs one, once we know what kind of gun he wants,” Mmemme told me. I asked him if he was afraid of being caught. “Nobody knows that I’m doing all these things unless you want a gun. I only sell to people I trust, or the people they trust,” he said. And besides, “I’m not afraid of the police and the military; we have sold to policemen who keep the guns for personal safety.”

Mmemme skirted my questions about how guns in the wrong hands could worsen the situation. Much of the violence in the Middle Belt results from politicians deploying young vigilantes to create havoc, stirring up ethnic and religious strife to help them secure elections, according to youth, community leaders, and politicians themselves. Grievances over land and resources have also spurred revenge killings.

Mmemme has sold guns used in clashes between Muslims and Christians, such as an incident, last year, in which a group of men from the Muslim Hausa ethnic group came to pray at a neighborhood mosque and some Christians he knows attacked them. Guns are everywhere; in rural settlements outside of Jos, little boys of the Muslim Fulani ethnic group have been seen herding cattle armed with AK-47s. “We used to see guns only in action films,” Mmemme said. Now, he keeps a Mach IV near his bed and carries his hand pistol when he goes to clubs.

In the spring, Nigerian President Goodluck Jonathan set up the Committee on the Control of Small Arms and Light Weapons, a group meant to advise the government on how to stem arms trafficking in Nigeria. But while the committee has done considerable research on where the guns are coming from, where they are being made, and for how much they are selling, its work has not resulted in any significant new anti-trafficking policies.

The new arms-trade treaty could go further. It requires countries to regulate the flow of weapons across their international borders, control the arms that are exported, and report arms imports and exports to a national secretariat. It could also spur the government to install harsher penalties for arms trafficking and closer monitoring of arms sales and transfers. Currently, the punishment for selling or possessing illicit guns is a fine of only five thousand naira, about thirty dollars—hardly an effective deterrent.

If the government puts new rules in place, that could make it harder for gun entrepreneurs like Mmemme to find the parts he needs to assemble guns, hurting his business. Authorities have raided arms factories in Jos in the past, and upping their watch of gun ownership in the area could also lead them to Mmemme’s workshop. But because the treaty doesn’t cover gun control within its signatories’ borders, it’s entirely possible that Mmemme would be unaffected—or perhaps even helped—by policies directed at the international arms trade rather than locally produced weapons.

I’d lost touch with Mmemme since we met in Jos last year. I wrote about him in May but wondered, more recently, how he expected the treaty would affect him. When I called him this week, he said that he hadn’t heard of it and that business was doing “fine.”

Mmemme would never tell his mother that he supplies guns; he doesn’t think she would understand, and he doesn’t want to hurt or embarrass her. Still, he believes his mission is ordained by God. “The pastors will not tell you to go out and buy a gun, but they will tell you that you should protect yourself,” he said. “That you should have something you can protect yourself with.”

Nonetheless, he appeared tormented at times by his choice of vocation. He said he was “not happy being like this” and craved a place where he would feel safe. Even the men who work in the arms-production workshop operate in mutual distrust, telling each other only as little about themselves as possible, Mmemme told me.

Dauda Saidu, a psychiatrist at the Jos University Teaching Hospital, said he had seen a sharp rise in cases of post-traumatic stress disorder amid the conflict. As for young people like Mmemme, he said he understood his extreme reaction: “You need some degree of paranoia to survive in this environment.”

Nigeria’s government promises to try to end the killings. But the Middle Belt erupts in violence whenever elections coincide with an abundance of illegal arms and the presence of scared, vengeful young people. With local weapons to fuel that violence, it’s doubtful that an international treaty will be able to hold off that potent combination.

Alexis Okeowo is a journalist based in Lagos. She received support for the reporting in this post from the International Reporting Project Fellowship in Global Religion Reporting.

See a slide show of photographs from Nigeria.