Members of a Jewish disaster relief organization appeared at the market to ensure all of the victims’ body parts were collected, according to religious custom. The same practice is carried out in Israel after terrorist bombings and other attacks.

A rabbi would later confirm that Mr. Deutsch’s body had been riddled with bullets. “Can you imagine, a few hundred bullets into the body of a 24-year-old child?” he said, sobbing.

A vigil was held for Michael Rumberger, the father of two left in a car trunk who may have been the first victim, the link still unclear to his inconsolable parents.

And everyone grappled with the notion that the rampage had been an act of domestic terrorism, infringing on any sense of peace and exposing their vulnerability.

Chesky Deutsch, a community activist in the Hasidic community, would agonize over how to soothe frayed emotions. There was much to consider: holding proper burials, addressing the families of victims, relaying details from the police.

It was the thought of the young school children that particularly weighed on Mr. Deutsch. They would need therapists. Trapped beside a barrage of bullets, they had experienced a fear from which they could not be sheltered, their innocence forever fragmented.

“All they heard,” he said, “was gunshots for two hours.”

Reporting was contributed by Nick Corasaniti, Michael Gold, Kwame Opam, Sharon Otterman, William K. Rashbaum, Michael Rothfeld, Andrea Salcedo, Edgar Sandoval, Nate Schweber, Ashley Southall, Christiaan Triebert, Tracey Tully, Ali Watkins and Haley Willis. Susan C. Beachy, Jack Begg and Sheelagh McNeill contributed research.