The Afghan investigation was up-close and gruesomely personal. As Zer Gul, a local police commander, sorted through the body parts at the scene, in the Azra District of Logar Province, he concluded that nearly all the victims were police officers under his command, along with a few volunteers who were allies of the police force. He recognized the uniforms they wore, he said, but he also knew some of his own men by body parts he could identify.