Al-Zawahiri was on his Kabul balcony. How Hellfire missiles took him out

Two Hellfire missiles ended al Qaeda leader Ayman al-Zawahiri's life in a safehouse balcony in a wealthy neighborhood in Kabul, the capital of Afghanistan, at 6:18 a.m. Sunday, a senior administration official said Monday. 

The missiles were launched by an unmanned aerial vehicle, or drone, killing him instantly. 

The nature of the strike as described by a senior administration official signals that the U.S. may have used the R9X Hellfire variant, also known as the "Ninja" or "Flying Ginsu" missile, nicknamed for knives famously sold on TV in the 1980s. This variant has been used in the recent past to kill other extremist leaders.