Taliban gunmen stormed a military-run school in Peshawar a year ago and, during a rampage that involved taking 500 children hostage, killed more than 140 people.
Extremists such as Hafiz Saeed , the head of Lashkar-e-Taiba, which waged the 2008 attacks in Mumbai, and Abdul Aziz , the firebrand cleric of the Red Mosque in Islamabad who refused to condemn the Peshawar school attack, roam free and broadcast their views.
With the Pakistani Taliban fracturing, disaffected members could transfer their allegiances to Islamic State, heightening the risk of violence against Pakistani Shiites and other minorities.
In a jailhouse interview with Pakistan's Herald magazine earlier this year, Mr. Aziz hinted at several reasons he decided to kill Ms. Mahmud, including her "liberal, secular values" and her support for the celebration of Valentine's Day in Pakistan.
