The land mine that killed Ma Simet and two others was laid decades ago. The devices are designed to endure. They can outlast monsoons and droughts, years of political upheaval and submerged histories — until the cataclysmic moment of contact.

On Jan. 10, under an early hot sun, the men worked to remove mines from a field, vestiges of a time when Cambodia was at war with itself and suffered as a victim of a larger conflict. By late morning, they had discovered a Russian-made anti-tank mine. Nestled nearby, unseen by them, was an anti-personnel device, which targets anyone trying to defuse the larger explosive.

The two men closer to the detonation were obliterated. All that was left of one was a couple of fingers and a patch of scalp. Ma Simet, 32, was a bit farther away. His body was found intact.