PARIS: Slain Hamas leader Yahya Sinwar was seen as a key obstacle to any agreement on the Israeli hostages seized during the October 7 attack that he orchestrated. With his group plunged into a leadership vacuum by his death, the future of hostage negotiations appears to have become even more complicated. Hamas now needs to appoint a replacement, and that person will play a key role in determining the fate of the Israelis kept hostage since its attack on October 7, 2023.