AL-HOL CAMP, Syria — The killings have taken on a creeping sense of inevitability, guards say. No one admits to hearing them, let alone knowing who is responsible.

On a recent morning, officials inside al-Hol detention camp said it was still too dangerous to try recovering the latest pair of corpses discovered overnight. “We’re still investigating,” said an exhausted camp guard, slumping in her office chair, her shirt rumpled and ponytail messy after a night without sleep.

Since January, officials report, more than 70 people have been killed inside northeast Syria’s al-Hol camp, which houses 62,000 family members of Islamic State fighters and others detained during the collapse of its self-declared caliphate more than two years ago.