WASHINGTON - The death of Osama bin Laden has drawn attention to the role Iran might play in al-Qaeda's future, as intelligence officials around the world analyzed reports that Saif al-Adel, one of the group's founders, had taken over as its interim leader.

Adel was last known to be detained outside Tehran.

His resumé includes helping to orchestrate the 1998 bombings of U.S. embassies in Africa. But he had sharp disagreements with bin Laden and opposed the Sept. 11, 2001, terrorist attacks. He accurately predicted that inciting the wrath of the United States would hurt al-Qaeda's worldwide efforts.

Adel is among the many senior al-Qaeda figures who fled into Iran after the U.S. invasion of Afghanistan. They were arrested there in 2003 and placed under house arrest in a compound outside Tehran.

The United States is not sure why Iran occasionally allows the al-Qaeda figures to travel and why they return. They are suspected of taking smuggling routes heading toward Saudi Arabia or Pakistan.

Noman Benotman, a former jihadist with links to al-Qaeda in Afghanistan, Pakistan, and Sudan who is now a security analyst in London, said Adel would serve as al-Qaeda's interim leader until bin Laden's permanent successor is named.

It's unclear where Adel is. Some analysts and intelligence officials have said he left Iran last year and rejoined al-Qaeda in the lawless region along Pakistan's border with Afghanistan. Adel is among the FBI's most-wanted terrorists and the United States is offering a $5 million reward for his capture.

Though Western and Arab intelligence officials said they had seen no hard evidence that Adel had taken over, his emergence as even a possible successor to bin Laden has renewed questions about the al-Qaeda figures who have been held in Iran.

Iran and al-Qaeda have a relationship of convenience, not an alliance. The Shiite regime in Tehran is generally hostile to the Sunni terrorist organization, but they have a shared enemy in the United States.

If Adel or any of the other senior figures were released, Iran would be in violation of a U.N. resolution. But if Adel has already returned to al-Qaeda's active leadership, it means two of the organization's most senior commanders have Iranian ties.

The other is Atiyah Abdul-Rahman, whom the United States considers the No. 3 figure in the terrorist group.

Abdul-Rahman was the organization's emissary in Iran. Over the years, he has been allowed to travel in and out of the country. Richard Barrett, a U.N. official, said Wednesday that Abdul-Rahman had been operating out of Pakistan's tribal regions for some time.

Adel brings to the table a calculating leadership and a murderous past.

"He is the most ruthless leader in al-Qaeda. When he was head of security intelligence, he rounded up so many of the spies and executed them," said Rohan Gunaratna, head of the International Center for Political Violence and Terrorism Research in Singapore.

Still, the 9/11 Commission reported that Adel was among a few aides who urged bin Laden not to carry out the attacks.