Ten years have passed since Ajoon Khan’s son died in a ghastly attack by the Pakistani Taliban that killed about 150 people, mostly children, at a military-run school in Peshawar, in northwestern Pakistan.

But the pain of loss is unrelenting — it grows only deeper with time. Khan, a lawyer, said he could never forget the parents sobbing and pleading outside the school gates, the soldiers storming the building, the children and the teachers fleeing in terror.

"It has been nearly a decade, but it feels like nothing has changed,” said Khan, speaking last week, just before the Dec. 16 anniversary of the death of his son, Asfand, who had been in the 10th grade. "If you look at the security situation in the country, it feels that our children’s sacrifices were in vain.”