Taliban struck a police station Wednesday. Many police are resigning because of death threats.
The Army launched fresh operations this week, following mounting pressure to retake the onetime tourist idyll now controlled by ultraconservative militants.
The group controls large areas in the Swat Valley and runs a parallel court system under sharia law.
Key Taliban figures in the tribal belt remain at large despite 20,000 troops' efforts.
In a FRONTLINE/World joint project, reporter David Montero talks about meeting a reclusive Taliban cleric, known as the "Radio Mullah."