Who was Saleh al-Arouri, the Hamas leader killed in Beirut?

Killing of the deputy chief of Hamas’s political bureau could spark retaliation from Hamas and Hezbollah.

source https://www.aljazeera.com/news/2024/1/3/who-was-saleh-al-arouri-the-hamas-leader-killed-in-beirut?traffic_source=rss