WASHINGTON, Jan. 18 (UPI) -- An Afghan colonel, who shot and killed eight U.S. airmen and a civilian contractor in Kabul last April, had acted alone, says a U.S. Air Force investigation.
The shootings occurred April 27 at the Afghan Command and Control Center at North Kabul International Airport, the Defense Department said on its Web site.
The attacker, Afghan air force Col. Ahmed Gul who had also injured several Afghans, was killed during the incident.
The U.S. Air Force Office of Special Investigations reported Gul acted alone but did not give a conclusive motive for the killings.
The attack, however, appeared to be premeditated, and witness statements indicated Gul may have had personal issues that may have compounded his financial problems, the report said.
The investigation did not support media reports shortly after the incident that an argument may have occurred earlier that day between Gul and the American service members.
Since the shootings, several security initiatives have been taken to improve protection for coalition advisers, officials of NATO's International Security Assistance Force were quoted as saying.