U.S. military investigators found no conclusive evidence that an Afghan officer who killed eight U.S. airmen and one U.S. civilian during a meeting in Kabul in April had ties to the Taliban, according to a report released Tuesday.
But the gunman, who shot each of the Americans multiple times after arriving for a routine meeting at an Afghan air force headquarters compound, previously had vowed to "kill Americans," the report said.
The incident _ among the deadliest of its kind during the 10-year-old war _ showed the dangers faced not only by U.S. troops on Afghan battlefields but also those military and civilian trainers and advisers who work daily with Afghan forces to prepare for the eventual departure of international troops.
Gen. Norton Schwartz, the Air Force chief of staff, praised the victims' bravery and said they have left behind "an honorable legacy that we continue to see in the commitment of airmen who serve as air advisers today."
The 436-page report by the Air Force Office of Special Investigations determined that Col. Ahmed Gul acted alone, but it found no conclusive motive for the deadly shooting spree at Kabul International Airport.
The report was dated Sept. 4 but not released until Tuesday.
Investigators cited evidence that Gul had financial and other personal problems, and that he may have had Taliban sympathies. But they could not establish with certainty why, at 10:10 a.m. on April 27, 2011, Gul entered the air command and control center, pulled a black Smith & Wesson 9 mm pistol from a holster and began an attack that ended only after Gul apparently turned the gun on himself.
Before dying, he wrote in blood _ apparently his own _ on a wall in a hallway of the control center, "God is one" and "God in your name" in Dari, a Persian dialect spoken in Afghanistan, the report said.
One unidentified Afghan told investigators that after living in Pakistan for about 18 months Gul returned to his native country in 2008, and that he told others he came back because he "wanted to kill Americans."
Air Force investigators, with help from other U.S. government agencies, consulted intelligence documents and other materials to try to determine Gul's possible motive.
"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 report said. "Additionally, there are multiple reports that indicated subject (Gul) may have had mental issues" possibly compounded by money problems.
In reconstructing the shooting, the investigation report described a chaotic scene as word spread incorrectly among the Americans that a suicide bomber was in their midst. A number of people jumped from a window to escape. One witness told investigators that Gul's initial barrage of gunfire lasted at least 30 seconds.
"All of a sudden a man comes through the door and starts shooting," one witness wrote.
Others described Gul as shooting continuously in multiple directions. They said he stopped at least once to slip a fresh ammunition magazine into his pistol. At a certain point at least one of the Americans fired back, apparently wounding Gul.
The names of all witnesses were blacked out in the report for privacy reasons.
Another witness recounted running and locking himself in a nearby room, hoping to stay alive. Others, including airmen whose role was to mentor the Afghans on air operations, pleaded to be spared.
"I hear, `ah, ah, ah' from the mentors who were being shot ... after the first round, many mobile phones began to ring on the bodies of the mentors," the witness said. "I thought it was strange how fast people started to call."
"For the second round of shooting, he came back to finish off the mentors that may have still been living from the first round of shots," said the witness, adding that he heard one victim begging not to be killed _ then four shots rang out.
The shooter then tried to get into a nearby radio room and a computer room but could not because they were locked; he left and went to the second floor. There he fired a round into a closed door in the intelligence office's reception area. He then sat on a couch and fired two fatal rounds into his chest.
On the cell phone of the only female victim, Master Sgt. Tara R. Brown, 33, of Deltona, Fla., investigators found she had received a text message, just moments after the rampage began, saying help was on its way: "Keep head down, lock and load."
Shot in the head, shoulder and buttocks, she was taken alive from the scene and was said by one witness to have managed a smile en route to the hospital, where she died.
The seven other airmen killed were officers ranging in rank from captain to lieutenant colonel. The civilian victim was a contractor, retired Army officer James McLaughlin Jr., 55, of Santa Rosa, Calif.
Robert Burns can be reached on Twitter at http://www.twitter.com/robertburnsAP