"He would read Israeli newspapers on a daily basis. He understood them way better than they understood him - hence his ability to deceive them and catch them off guard by executing his military operation so effectively in October 2023," an expert tells Sky News. The new leader of Hamas's political bureau was the architect of the 7 October attack, according to Israel. Yahya Sinwar has led Hamas within Gaza since 2017, having joined its ranks in the early 1980s.