The United States killed al Qaeda boss Ayman al-Zawahiri in a drone strike Saturday, following a more than 20-year effort to assassinate the terrorist. Labeled by US officials as Osama bin Laden’s number-two, al-Zawahiri, 71, was a key plotter of the September 11 terrorist attacks and took over as the leader of the notorious terror group following bin Laden’s death in 2011. The strike was carried out early Sunday at an Afghanistan safe house the elderly terrorist had be holed up in, at 6:18 am local time and 9:48 pm Saturday in the US. The early morning attack saw al-Zawahiri...