Whitehotpix / ZUMA Saad bin Laden, son of Osama, was a prominent figure in the relationship between Iran and al-Qaeda

It may have been a case of hitting the target but missing the opportunity. Reports last week said Saad bin Laden, Osama bin Laden's fourth son and a midranking al-Qaeda operative, was killed by a recent CIA Predator strike. But six years ago, the U.S. had an opportunity to get him alive  and lost it when the Bush Administration decided to pull away from cooperation with Iran. (Read "Obama's Unlikely Ally: Iran Signs On to Afghan Plan.")

Saad's death has not yet been confirmed, but U.S. officials believe he was one of the victims of a missile strike earlier this year in northern Pakistan. A counterterrorism official tells TIME, "There are some indications that he may be dead, but it's not 100% certain." (Read "Archive: Osama's Son Also Rises.")

Believed to be in his late 20s, Saad is one of two bin Laden sons known to be actively involved in their father's jihadist enterprise; his older brother Mohammed is still at large, believed to be in Pakistan. (Osama has at least nine other sons and six daughters.) Saad had only recently returned to the Afghan-Pakistani border after nearly six years under house arrest in Iran. He was one of several al-Qaeda commanders, including military chief Saif al-Adel, captured by Iranian authorities in the spring and summer of 2003 as they tried to sneak across the border from Afghanistan. (See pictures of Osama bin Laden.)

At the time, the Bush Administration and the Iranian regime were secretly cooperating in the fight against al-Qaeda and the Taliban. In February of that year, Iranian officials had given their U.S. counterparts photocopies of the passports of more than 200 Arabs  including Saad bin Laden  who had been turned away at the Afghan border. The Iranians worried that many of them would enter the country illegally through the porous border. Hillary Mann Leverett, then an official with the National Security Council and one of a handful of Americans involved in negotiations with Tehran, says the Iranians were concerned that if Saad snuck in, they would not be able to repatriate him to his native Saudi Arabia, because authorities in Riyadh were unwilling to accept any of Osama's kin.

What the Iranians wanted was a multilateral mechanism, initiated by the U.S., to get the Arab intruders off their hands. Such a mechanism would have given U.S. interrogators access to the al-Qaeda operatives (whom the Iranians would presumably have detained if they once again tried to cross the border). But, says Leverett, the Bush Administration insisted that the Iranians deport the Arabs without any preconditions. By May, negotiations between the two countries broke down, and the chance was lost. Shortly thereafter, Saad bin Laden succeeded in crossing the border. Details of what happened next are murky, but he didn't get far: the Iranian authorities seem to have nabbed him almost immediately. (See pictures of the battle against the Taliban.)

Later that summer, after the U.S.-led coalition toppled Saddam Hussein's regime in Iraq, the Iranians came up with another offer: they would trade their Arab captives, including Saad, for members of the Mujahedin-e-Khalq (MEK), an Iranian terrorist group that was given sanctuary by Saddam. "It was a straightforward swap: your terrorists for ours," says a Western intelligence official familiar with Tehran's offer. The official says the offer included assurances that the MEK operatives would not be tortured and that international human-rights organizations would have access to them. "They said, 'We'll let the Red Cross or Amnesty [International] monitor the MEK prisoners, and we won't put them into some Guantánamo-like prison,' " says the official.

But the Bush Administration would have none of it. "The Americans just couldn't bring themselves to trust the Iranians, even though they had been pretty straight in their dealings over al-Qaeda and the Taliban," says the official. Instead, the U.S. decided to protect the MEK, even over the objections of Iraq's elected government. (Read "Bin Laden's Son Loses Political-Asylum Bid in Spain.")

Now, with the U.S. military presence in Iraq beginning to draw down, the government in Baghdad has made it clear that it will evict the MEK, though not to Iran. (Iraqi troops forced their way into the MEK's camp north of Baghdad on July 28.) Given the decline of the MEK's fortunes in Iraq, Tehran seems to have decided in late 2008 that the al-Qaeda commanders under house arrest had lost their value as bargaining chips. Several of them, including Saad bin Laden, appear to have been taken to the border with Pakistan and released. For Saad, however, freedom lasted only a few weeks before he was allegedly killed by a Hellfire missile.

How might the U.S. have benefited from interrogating Saad instead of killing him? We may never know. Saad "was a small player with a big name," says the counterterrorism official. "He has never been a major operational figure." (His brother Mohammed is thought to be more influential.) But terrorism analyst Peter Bergen, author of Holy War Inc.: Inside the Secret World of Osama bin Laden, points out that having Saad bin Laden in custody "would have been a great propaganda victory" for the U.S., greater than his death could be. Adds the Western intelligence official: "Think of how Americans would feel about Guantánamo if one of Osama's sons was among the detainees."

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