ISLAMABAD, Pakistan — One morning last week, television viewers in Pakistan were treated to a darkly comic sight: a posse of middle-class women roaming through a public park in Karachi, on the hunt for dating couples engaged in “immoral” behavior.

Panting breathlessly and trailed by a cameraman, the group of about 15 women chased after — sometimes at jogging pace — girls and boys sitting quietly on benches overlooking the Arabian Sea or strolling under the trees. The women peppered them with questions: What were they doing? Did their parents know? Were they engaged?

Some couples reacted with alarm, and tried to scuttle away. A few gave awkward answers. One couple claimed to be married. The show’s host, Maya Khan, 31, demanded to see proof. “So where is your marriage certificate?” she asked sternly.

This hourlong spectacle, broadcast live on Samaa TV on Jan. 17, set off a furious reaction in parts of Pakistan. Outrage sprang from the Internet and percolated into the national newspapers, where writers slammed Ms. Khan’s tactics as a “witch hunt.”