Complex sentence: Residents of the neighborhood said two brothers who were Hamas fighters were in the area at the time of the attack but that the mortar fire had not come from the school compound, but from elsewhere in the neighborhood.
Split into simpler sentences: Residents of the neighborhood said two brothers who were Hamas fighters were in the area at the time of the attack. But the residents also said the mortar fire had not come from the school compound, but from elsewhere in the neighborhood.