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

Mr. Melahy disappeared from his home a few days before the Taba attacks and, his family said, has not been seen since. The police say he is alive and believed to be hiding in the mountains to the south.

The trajectory of his life is similar to others the police say have been involved in these attacks, like the Felaifel brothers, who were connected to the bombings in Taba and Sharm el-Sheik. Their father said that he disowned his boys — a drastic act in Bedouin culture — after they grew beards and began preaching an extremist religious ideology, telling him he did not dress right, or pray right, or eat right.

Religious extremism began to arrive here in the 1980’s, just as the tribal traditions that governed the people of the Sinai for centuries were slowly being undermined both by the state and by a rising influence of conservative religious ideology alien to this region.

The Muslim Brotherhood from Egypt had worked here, but it was the arrival of Wahhabism that began to change the local culture, people here said. Women, for example, have abandoned the traditional Bedouin dress for the far more concealing Islamic gown popular in the Persian Gulf.

"Bit by bit, more people are becoming religious extremists," said Mahmoud al-Sawaraka, 49, a leader of one of the region’s largest tribes. "Late in the 1980’s it really started and it is mostly young people."

There has always been a degree of distrust between the Egyptians of the Nile Valley and the Bedouins of the Sinai, a distrust that grew after Israel ended its 12-year-occupation.

Those who lived through the occupation said Egyptians from the other side of the Suez Canal always questioned their loyalty to the state and blocked them from positions of influence in the military, the police and even within their own government.

"We are not the Kurds of Egypt," said Ashraf Ayoub, a local political leader. "The government keeps calling us Bedouin as if we are third-class citizens."

The modern Egyptian state has dealt with the Sinai and its people the way it has confronted most domestic problems, as a security issue. Local officials, for the most part, are not from the area, and no one is allowed to own land because the entire area is considered a military zone, officials here said.

But the authorities in Egypt say the treaty that ended the Israeli occupation of the Sinai constrained their ability to deploy forces across the peninsula’s vast and rugged expanse. So they demanded the aid of the Bedouins and their leaders.

For centuries, tribes collectively selected their sheik until the Egyptian government decided that it needed to make the tribal leader an arm of the state security.

First slowly, and then more rapidly, religious and government pressures began to undermine the one institution that served to maintain public order: the tribe.