An American flag hangs outside the Falls Church, Virginia, home of Maj. Gen. Harold Greene. Two stars are visible in the window, reflecting his rank.
Greene was killed Tuesday while visiting a military academy in Afghanistan -- the highest ranking U.S. official to have been killed in action since the Pentagon attack on Sept. 11, 2001. Greene, who served 34 years in the Army, was an engineer who rose through the ranks as an expert in developing and fielding the Army's war materiel.
Greene's visit to an Afghan military academy was supposed to be routine, with the general there to observe progress made by the Afghan troops in training.
"He really believed in what he was doing there and was really proud to serve," said Lt. Col. Juanita Chang.
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But Tuesday's meeting was interrupted by gunfire. One of thousands of the Afghan security forces trained by the United States opened fire, killing the general and wounding 15 others, including eight Americans, one of the bloodiest insider attacks during the war in Afghanistan.
Within seconds, soldiers fired back, killing the gunman.
Greene had been sent to Afghanistan in January -- his first deployment to a war zone -- following a promotion to deputy commander of training in Afghanistan.
Greene flourished in the less glamorous side of the Army that develops, tests, builds and supplies soldiers with equipment and technology. That is a particularly difficult job during wartime, since unconventional or unanticipated battlefield challenges like roadside bombs in Iraq and Afghanistan, call for urgent improvements in equipment.
Military officials were saddened to learn about Greene's death.
"The loss of this individual will be very, very difficult on the force as a whole," said retired Gen. Peter Chiarelli.
The Army's top soldier, Gen. Ray Odierno, issued a statement Tuesday evening saying the Army's thoughts and prayers were with Greene's family as well as the families of those injured in the attack.
"It is their service and sacrifice that define us as an Army," Odierno's statement reads.
Greene received his two-star promotion in August 2012. His wife, Sue Myers, a retired colonel; daughter Amelia, a recent college graduate; and son Matthew, also an active duty soldier, were by his side during the promotion ceremony.
Beyond his service, Greene was also a scholar, holding a Ph.D. and three masters degrees. The registered engineer was a New York native.
The Associated Press contributed to this report.
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