It seemed as if there was little trace of human life left in the wake of Hamas’s attack in southern Israel a month ago — just a desolate trail of burned homes, scorched rooms, bullet-scarred doors and charred cars.

Volunteers from Israel’s high-tech industry initially helped authorities try to identify the dead and missing, using artificial intelligence to sort through photos and videos. Yet still dozens of people were left unaccounted for after the worst day of violence in the nation’s history.