"You!" he shouts at a driver trying to sneak past his checkpoint, his cherubic face turning violently angry.
I hurt for the leader whose platoon killed 10 civilians who did not stop as they approached his checkpoint.
A half-hour after Mr. Muhammad spoke, a policeman detained for letting the car bomb pass through his checkpoint tried to escape.
He had a gash on his nose and his right eyebrow; he said that the rebels had attacked his checkpoint, and he had "fallen down" while trying to run away.
At his checkpoint in Omarkhel village, Rahman told me that as bad as it had sometimes been in Shahabuddin, he had only made the 20-minute drive to Pul-i-Khumri Pul-i-Khumri Pul-i-Khumrir.
While the young rebel sat at his checkpoint, and while Americans continue to debate whether to intervene in Syria or just look the other way, Islamist militants are exploiting the uncertainty here.
Following a weekly routine, he spent a recent Saturday with his family at home north of Kabul and was returning to his checkpoint that afternoon when the bomb exploded under his truck, dead center.
Mr. Jan said that he had heard the shooting from his checkpoint, but that because it had not lasted long, he and his colleagues had not thought much of it.
Also in June, one screener was arrested in Philadelphia for stealing $335 from a passenger passing through his checkpoint, and 13 screeners were arrested in New Orleans on charges of stealing valuables from checked luggage.
