"Deep mistrust between US & Afghan forces"

"...The report released Tuesday by the Pentagon revealed that the Afghan colonel — who methodically opened fire in a conference room at a highly secured Afghan air base in April — told friends that he had returned to Afghanistan from Pakistan "to kill Americans."... 
The 436-page report by the Air Force Office of Special Investigations said there was no evidence that Gul, who killed himself after the incident with two self-inflicted shots to the torso, was a member of the Taliban....
But investigators — who interviewed witnesses, other U.S. trainers and Afghan officers and airmen — found that the relationship between Afghan troops and their American mentors is often filled with hostility bordering on hatred. These tensions continue even after a decade in which the U.S.-led NATO coalition has closely trained Afghan forces that it describes as its allies. ..."