On Friday afternoon, it was hard to see the remains of any structure, let alone infrastructure, at the site of the Thursday airstrike. All that was left of the al-Swarka family’s two homes, which had been about 50 yards apart, were shards of two tin shacks strewn across giant craters in the sand.

Neighbors told The Associated Press that an Islamic Jihad commander had lived in one of the destroyed homes, but that he wasn’t home at the time of the airstrike.

But Ismail al-Swarka, the brother of one of those killed, gave a different account.

One of the destroyed homes, he said, belonged to Rasmi Abu Malhous, who sometimes used the surname al-Swarka, the name of their populous Bedouin tribe. He received a police officer’s salary from the Palestinian Authority, though like many others on the payroll of the authority, idled years ago in Gaza for political reasons, he did not actually put on a uniform and go to work.

One of Mr. Abu Malhous’s two wives, Mariam, was killed, Ismail said; the other, Wissam, survived. Three of his children were killed.

In the other home lived Mohammad and Yousra al-Swarka, Ismail’s sister.

Mohammad works for Palestinian Islamic Jihad but in a civilian capacity, the group said, mediating disputes between families and performing other social functions.

“Why are the children killed if the Israeli army has a problem with someone?” asked Dawood Shihab, an Islamic Jihad spokesman.

Yousra was killed in the blast, her brother said, along with two of the family’s six children.

Ismail al-Swarka said the Israelis gave no warning before firing on his relatives’ homes. After he rushed outside after the airstrike, he said he was disoriented by what he found. “It was unrecognizable,” he said. “I didn’t know what to do.” He found one nephew’s body at the edge of a crater. Then a neighbor stumbled across an adult’s body.