On the morning of July 31, al-Qaeda leader Ayman al-Zawahiri, who has been in hiding since 9/11, walked onto the balcony inside a compound in downtown Kabul. The Egyptian-born physician had taken over the leadership of the terrorist organization after US Navy SEALS killed Osama bin laden in Abbottabad in 2011. For 11 years he had directed al-Qaeda from the shadows and there had been many false starts for the US intelligence agencies and special operations team who were tracking him. But on this day, as he stood outside, a US directed hellfire missile, reportedly fired from a drone killed him. The missile was incredibly precise, it killed the al Qaeda leader but not his family, who are believed to have been inside the building at the time.

Air to surface missiles like this one are just one of the tools that US counter-terrorism teams have been using as they hunt down terrorist leaders around the globe. While Zawahiri's killing was seen as the end of a long and costly manhunt – both in human lives and resources – what does his death mean to the future of the al Qaeda?

I spoke recently with retired Lieutenant Generals Scott Howell and Mike Nagata. Lt. Gen Howell served as Commander of Joint Special Operations Command Central before he retired just over a year ago and Lt. Gen Mike Nagata served as Commander of US Special Operations Command before retiring in 2019.

As the first Air Force officer to command JSOC, Lt Gen. Howell led a force of 14,000 personnel engaged in special operations across multiple areas of instability and was responsible for the readiness and mission execution of highly-specialized forces of the Army, Navy, Air Force, and Marines.

And Lt. General Nagata's final position before retiring was Director of Strategy for the National Counterterrorism Center – a job he held from 2016 to 2019. He served as Commander of US Special Operations Command-Central and was responsible for Special Operations across the Central Command region from 2013 to 2015 and was heavily involved in the first two years of combat operations against the Islamic State in Iraq, Syria, and elsewhere.