CAIRO — Seven years later, it remains conventional wisdom here that Osama bin Laden and Al Qaeda could not have been solely responsible for the attacks of Sept. 11, 2001, and that the United States and Israel had to have been involved in their planning, if not their execution, too.

This is not the conclusion of a scientific survey, but it is what routinely comes up in conversations around the region — in a shopping mall in Dubai, in a park in Algiers, in a cafe in Riyadh and all over Cairo.

“Look, I don’t believe what your governments and press say. It just can’t be true,” said Ahmed Issab, 26, a Syrian engineer who lives and works in the United Arab Emirates. “Why would they tell the truth? I think the U.S. organized this so that they had an excuse to invade Iraq for the oil.”