DU CHEE YAR TAN, Myanmar — Under the pale moon of Jan. 13, Zaw Patha watched from her bamboo house as Mohmach, 15, her eldest child, was dragged from the kiosk where he slept as guardian of the family business.

The men who abducted the boy struck him with the butt of a rifle until he fell to the dirt path, she said in an interview, gesturing with a sweep of her slender arms. Terrified, she fled into the rice fields. She assumes he is dead.

Three doors away, Zoya, dressed in a black abaya, showed the latch on her front door that she said armed men had broken as they stormed in and began beating her 14-year-old son, Mohamed. She has not seen him since.

The villagers’ accounts back up a United Nations investigation, which concluded that the attack on Du Chee Yar Tan that night resulted in the deaths of at least 40 men, women and children, one of the worst instances of violence against the country’s long-persecuted Rohingya Muslims. They were killed, the United Nations says, by local security forces and civilians of the rival Rakhine ethnic group, many of them adherents of an extreme Buddhist ideology who were angered by the kidnapping of a Rakhine policeman by some Rohingya men.