For all that, his captors betrayed glimpses of humanity, even humor: small acts of kindness; quirky after-dinner games; shared confidences and reminiscences. But their ruthless intent was never in doubt, the former hostage said, speaking anonymously because he feared reprisals against his family.

During his captivity, four teenage suicide bombers were undergoing instruction, taking indoctrination classes in the morning and carrying mock explosive vests equipped with push-button detonators in the afternoon.

“Their mantra was: ‘One button and you go to heaven,’ ” he recalled.

Kidnapping is a centuries-old scourge in parts of Pakistan, from the tribesmen who snatched British colonists in the 19th century to the slum gangs that have preyed on Karachi business families since the 1980s. The national total has varied only slightly in recent years: from 474 kidnappings for ransom in 2010 to 467 last year, according to Interior Ministry figures.

What has changed, however, is the level of Taliban involvement.

In one case, a 70-year-old German aid worker and his 24-year-old Italian colleague, who disappeared from the city of Multan on Jan. 20, are being held by militants in North Waziristan, a senior security official confirmed.

Others in militant captivity include Shahbaz Taseer, son of Salmaan Taseer, a Punjab governor who was assassinated; two Swiss tourists who vanished as they drove toward the Iranian border; the son-in-law of a retired four-star army general; and Warren Weinstein, a 70-year-old American snatched from his home last August, days before he was due to leave Pakistan, and said to be held by Al Qaeda.