Police spokesman Micky Rosenfeld says the investigation has found that the Israeli man lost control of his car after he was hit in the head by a stone. Palestinian youths regularly throw stones at Israeli cars in the West Bank.

Israel’s Defense Ministry said on Wednesday that the “results of the investigation show it was a terror attack.” The crash was initially thought to have been an accident.

The father and son were residents of a nearby Israeli settlement.

Friday’s crash took place amid tensions in the West Bank linked to a Palestinian attempt to win UN recognition of a Palestinian state.