We were at risk, but we were especially worried about the girls. If Boko Haram found out these girls had failed to detonate their bombs, they could possibly be killed. And if regular people discovered they had spent time with Boko Haram, even as hostages, they could be stigmatized as sympathizers. We settled on a quiet park, a hotel room, an empty restaurant.

Adam’s job was particularly difficult. Imagine being tasked with taking portraits of girls whose faces, we felt, should not be shown?

The girls did not request anonymity, but based on the advice of our local fixer, we obscured their faces and did not use their full names. The girls seemed relieved to have the chance to tell their stories.

I knew from my experience reporting on the insurgency that these girls had been through a string of horrible circumstances, beginning with their capture. Some had family members killed before their eyes. Fighters stuck one girl in a room with corpses, and when militants asked about her strength, she presumed they wanted her to clear the bodies. But they wanted her to carry a bomb.

Far from willing participants, each girl said that the armed militants had forcibly tied the bombs to them — many times after they had refused to have sex with their captors.

I tried to get the girls to explain their suicide missions. “What happened when Boko Haram told you to carry a bomb?” I asked. Their stories flowed.

Every one of the 18 had a narrative worthy of a dissertation on the horrors of war. Some of the girls cried as they recalled their terror. Some told their stories in squeaky voices that revealed their young age. Others were fierce, proud of how they had saved lives by not carrying out their missions.