On a Sunday afternoon last August, Ahammed Hossain hid for four hours in a pond in his village of Chut Pyin, screened by bushes and thorns. Around him, he recalled, there was gunfire and the cries of men, women and children trying to outrun the deadly force of Myanmar’s 33rd Light Infantry Division.
About a quarter of the village’s Rohingya Muslims, more than 350 people died that day, Mr. Hossain said, which would be one of the largest massacres by Myanmar‘s security forces since the military initiated its campaign against...