JERUSALEM — Israeli Prime Minister Benjamin Netanyahu vowed revenge Friday for what he described as a “cruel and malicious violation” of the ceasefire agreement after authorities determined that a body released by Hamas as part of the deal was not an Israeli mother of two small boys, as the militant group had promised.

Israeli specialists said one of the four bodies handed over by Hamas on Thursday was not Shiri Bibas, whose two sons, Kfir and Ariel were handed over.