‘She Just Fell Down. And She Died.’

Myanmar’s security forces have killed more than 40 children since February. Here is the story of one, Aye Myat Thu. She was 10.

In the swelter of the hot season, U Soe Oo cracked open the coconut with practiced blows of his machete. Small hands reached out for the first slice, cool and slippery. His daughter — 10 years old, with dreams of being a makeup artist or a nurse or maybe even a princess with long golden hair like the one in “Maleficent,” which she had watched a zillion times, no joke — ran down a path with her sweet prize. Just as she reached the trees that marked the perimeter of their property, the girl seemed to stumble, landing flat on her stomach, her father recalled. The piece of coconut slipped from her grasp, falling onto the reddish earth of Mawlamyine, a port town perched on a slender archipelago in southeastern Myanmar.