When Rahim Khan summons Amir to meet with him in Pakistan, Baba's old friend informs him that Sohrab is in Kabul.
"I heard he's in an orphanage somewhere in Karteh-Seh." (Chapter 17)
But when Amir and Farid reach the orphanage, its director, Zaman, reveals that a Taliban official has taken Sohrab a month before. The Taliban regularly pays money for the children--"Usually he'll take a girl, but not always"--and Amir has to prevent Farid from strangling Zaman when the sale of the children is revealed. Zaman tells Amir and Farid to attend the soccer match at Ghazi Stadium the next day.
"You'll see him at halftime. He'll be the one wearing black sunglasses." (Chapter 20)
Amir does not recognize the blonde Taliban at first, but he soon will come to realize that it is his old enemy, Assef.