Ismail Haniyeh, the Hamas leader who was killed in Iran, was the tough-talking face of the Palestinian group's international diplomacy as war raged in Gaza, where three of his sons were killed in an Israeli airstrike. He has been the most visible leader of the group during Israel's war in Gaza and was key in ongoing ceasefire and hostage release negotiations. Is his assassination a blow to Hamas? Parmeshwar Bawa reports.