WASHINGTON -- Al-Qaida's second-highest leader, accused of being one of the masterminds of the deadly 1998 attacks on U.S. embassies in Africa, was killed in Iran three months ago, intelligence officials have confirmed.Abdullah Ahmed Abdullah, who went by the nom de guerre Abu Muhammad al-Masri, was gunned down on the streets of Tehran by two assassins on a motorcycle on Aug. 7, the anniversary of the embassy attacks. He was killed along with his daughter, Miriam, the widow of Osama bin Laden's son Hamza bin Laden.The attack was carried out by Israeli operatives at the behest of the United States, according to four of the officials. It is unclear what role if any was played by the United States, which had been tracking the movements of al-Masri and other Qaida operatives in Iran for years.Sign up for The Morning newsletter from the New York TimesThe killing occurred in such a netherworld of geopolitical intrigue and counterterrorism spycraft that al-Masri's death had been r