US military officials said Thursday there could have been more civilian casualties than initially thought in the raid that killed the top Islamic State leader in Syria last week, but they believe any such deaths were caused by the militant’s suicide bomb and were not at the hands of American forces. Laying out a chronology of the raid by special operations forces, officials also said they cannot be certain that Abu Ibrahim al-Hashimi al-Qurayshi detonated the bomb that killed him and his family at his home in the village of Atmeh near the Turkish border. But they said it was set off by him or …