According to MailOnline, Al-Dale'i was executed by ISIS militants as he climbed into a car in war-torn Aden, a port city in the south of Yemen.
Though no group initially claimed responsibility for the attack, Islamic State later released the first person footage, revealing how the callous attack was executed.
The film showed the gunman approach Dale'i with his weapon raised as the colonel steps into his car. He then pulls the trigger and the airport security boss was seen lying helplessly on the ground. There have been several assassination attempts on leading political figures and soldiers in the state.
ISIS militants have taken advantage of 19 months of the state’s civil war to expand their presence in Aden, city, which has now become Yemen's temporary capital.