Most nights, Godwin Mumbere and his classmates at Lhubirira Secondary School in Mpondwe on Uganda’s western border with the Democratic Republic of the Congo (DRC) study and sing quietly before turning off the lights at 10pm and climbing into their bunk beds. On June 16, that routine was disrupted by an unknown number of attackers, alleged rebels from the Allied Democratic Forces (ADF), who stole over the border from the DRC and set upon the school. Within hours, they had slaughtered more than two dozen pupils in the deadliest attack Uganda has experienced in decades.

Mumbere, 18, recalls that the assailants arrived about half past 10pm. They first shot the school watchman before demanding the boys open their dormitory door. “All my friends in the dormitory refused,” Mumbere told Al Jazeera.The head boy instructed them to hide beneath the beds, and Mumbere did as he was told while attackers fired bullets through the windows and the locked door.

Raiders proceeded to the girls’ sleeping quarters and killed the students there. Multiple medical personnel told Al Jazeera that most of the students were bludgeoned with hammers and hacked to death with machetes.The rebels also forced their way into the boys’ shuttered room, still firing guns. One of the bullets hit Mumbere in the hand. He wrapped it in a cloth. Finally, the militia set the boys’ dormitory on fire. So Mumbere took his chances and fled into the night.