Friend : Maj . Gen. Harold Greene 's focus was improving Americans ' lives . He earned two master 's degrees in engineering and a Ph.D. in materials science . Greene was one of the highest - ranking American military service members killed since 9/11 . Greene was the deputy commander of the Combined Security Transition Command , which is responsible for helping transfer security control in Afghanistan to the Afghans . He was an expert in infrastructure improvement and maintenance , the Pentagon says .
Friend : Maj . Gen. Harold Greene 's focus was improving Americans ' lives . He earned two master 's degrees in engineering and a Ph.D. in materials science . Greene was one of the highest - ranking American military service members killed since 9/11 . He was an expert in infrastructure improvement and maintenance , the Pentagon says .