Afghan colonel who shot dead Americans 'resented foreign troops' Investigators however dismissed reports in the aftermath of the attack on April 27, 2011, that suggested the shootings were provoked by an argument between Col Gul and US troops. Their 436-page report said: "This analysis is not stating that there are no insurgent connections to subject [Gul], but that none have been established thus far during this investigation," The 46-year-old opened fire as around two dozen people gathered for a routine meeting of officers training the fledgling Afghan air force. Witnesses described a scene of chaos with officers trying to jump through windows to safety and many in the airport believing they were under attack by a suicide bomber. Col Gul was wounded as officers fired back, but the attack was so unexpected that most victims could not defend themselves. As he moved from one room to another, he used blood to write "God is one" and "God in your name" on a wall in a hallway of the control centre. He also shouted out to Afghan soldiers not to approach, before eventually shooting himself dead in the chest. The shooting was the most deadly in a series of attacks on coalition forces by Afghan troops and police. The killings have prompted fears of widespread infiltration of the Afghan forces by the Taliban, though investigators have struggled to find motives for several incidents, or found they were driven by personal disputes. Air Force Chief of Staff General Norton Schwartz said: "These airmen paid the ultimate sacrifice while serving our nation in a combat zone." Each of these airmen bravely and purposely performed their duties, and their selfless sacrifices leave behind an honourable legacy that we continue to see in the commitment of airmen who serve as air advisers today.