CAIRO — Nour was 17 when he heard about the death of his teacher and nine friends in the span of few hours. He was at Rabia al-Adawiya Square on Aug. 14, 2013. “Seeing brains pouring out of people’s heads had become the norm for us that day,” he said. His account of the day is as disjointed as it is gory. It was like “a sea of blood. We stepped on the body parts of dead people.”

More than 1,000 were killed that day during simultaneous crackdowns on two sit-ins supporting ousted president Mohammed Morsi. At least 817 were killed in the eastern Cairo encampment of Rabia Square, according to a Human Rights Watch (HRW) report that described it as “one of the world’s largest killings of demonstrators in a single day in recent history.”

“We used to hear the buzzing sound [of bullets] around us, worse than any video game or action film,” Nour said.

Saved on his phone are pictures of his friends and his mentor Ahmed Ammar dying. The name also adorns a poster over his bed. According to testimonies collected by HRW, Ammar was killed by four bullets to the chest.