Out of Desert Poverty, a Caldron of Rage in the Sinai

"They destroyed the most important thing in the tribe, the power of the sheik," said Salah el-Bollak, a writer and expert in local Bedouin culture. "Now the sheik is nothing but an informer for the government."

People here said that the government inadvertently made the same mistake with the mosques, by requiring that all imams be employees of the state. That dictate undermined their credibility and sent people elsewhere for religious guidance, many local people said.

Mr. Sawaraka, who used his tribal name, not his family name, for fear of retribution from the police, said that the tribal system was also being undermined from another direction. One day a few years ago, he said, a package of religious books from Saudi Arabia was delivered to his house. He checked with the postal office and found it was meant for a young man with the same name.

"When I delivered the books, the father told me to throw them out and if any more ever came again, to throw them out too," he recalled.

As these forces gained momentum, the police say, local young men scoured the desert for explosives left from previous wars, and fashioned crude but deadly bombs in small workshops. People here say that any outside involvement was unlikely, as the community is so tightly knit, outsiders would have been noticed.

After the attacks on Dahab, police swept back into the area and chased Mr. Melahy and two others across northern areas of the Sinai Peninsula before finding their hideout between Gifgafa and Maghara in North Sinai. Since the manhunt began, the police said, six suspects have been killed in shootouts, and two officers, including a major.

The Interior Ministry said that machine guns, live ammunition and a notebook sketching the details of the two most recent terrorist attacks had been found. It said that the notebook proved that the attacks were planned by people from the Northern Sinai.

Abeer Allam contributed reporting for this article.