Discuss as:

After Gadhafi's demise, biggest killers of Americans now are dead

By Robert Windrem, NBC News' senior investigative producer

Since May 1, U.S. intelligence and special operations forces, or foreign forces working with U.S. intelligence and special operations forces, have killed the leading terrorists who targeted and killed more Americans than any others in the past 25 years.

Not only did the U.S. kill Osama Bin Laden on May 1, but also took out — "removed from the battlefield" — three of the jihadists they had identified as potential successors to bin Laden in the hours after the attack. Also, Somali forces loyal to the U.S. killed the mastermind of al-Qaida's East Africa embassy bombings. With 224 killed, 12 of them Americans, the attacks in Nairobi and Dar es Salaam were the group's deadliest attack before 9-11.

As for Moammar Gadhafi, it was his intelligence service that has been strongly linked to the attack on PanAm 103 in December 1988, which until September 11 was the single worst terrorist attack directed against the U.S., killing 269 people. (Gadhafi was also believed responsible for the deaths of 171 people on UTA 772 over the Congo.)

Here is the chronology:

May 1: Osama Bin Laden was killed by U.S. Special Forces in Abbottabad, Pakistan.

June 3: Ilyas Kashmiri, senior al-Qaida member and one of the five potential successors to al-Qaida leadership, is killed by a drone attack in Ghwakhwa area of South Waziristan, Pakistan.

June 8: Fazul Abdullah Mohammed, al-Qaida leader in East Africa and the mastermind of the East Africa embassy bombings was shot dead by Somali forces at a checkpoint in the capital. He was identified by a wanted poster provided by the U.S. military.

August 22: Attiyah Abd al-Rahman, newly minted No. 2 in al-Qaida, is killed by drone attack in North Waziristan. Attiyah was also seen by the CIA as potential successor to bin Laden and had served as bin Laden's "chief of staff" prior to the May 1 attack.

September 30: Anwar al-Awlaki, operational leader in al-Qaida in the Arabian Peninsula, is killed by drone attack in Yemen's al-Jawf province. He, too, had been identified as a potential successor to bin Laden.

October 20: Moammar Gadhafi, Libya’s leader for 42 years, was killed in a gun fight by Libyan rebels near Sirte.

U.S. officials remain confident that they are going to find and kill bin Laden’s successor, Ayman al-Zawahiri. Zawahiri himself admits he’s been targeted at least five times.

(Historical footnote: The Marine Barracks bombing in 1983 killed 241 U.S. servicemen and the East Africa embassy bombing and was until the Pan Am 103 bombing the single worst terrorist attack on the United States. It was the handiwork of Imad Mugniyah, who was killed in February 2008 in Damascus, Syria, by a bomb hidden in the headrest of a car. As he walked past the car, the bomb was detonated. It was believed to be the handiwork of a joint U.S.-Israeli operation.)