An American unmanned aerial vehicle (UAV) was hovering over the U.S. Consulate in Benghazi, Libya on September 11 during the attack in which bloodthirsty Al Qaeda-linked terrorists murdered Ambassador Chris Stevens and three others.

The military backup that should have been racing to the scene, launched in response by those monitoring the Predator drone and other reconnaissance aircraft, moved too slowly and came too late, charged a former CIA commander.

Gary Berntsen told CBS News this week that the savage attack on the consulate was observed in detail by top officials at the U.S. Defense Department as it took place. Terrorists armed with AK-47 assault rifles and rocket-propelled grenades (RPGs) launched a full-scale attack on both the consulate building itself, and the “safe house” located a short distance away.

It was to the second building, which also allegedly housed CIA operations, that Ambassador to Libya Christopher Stevens and three other American diplomats had been taken in the hopes of keeping them out of harm's way. But the effort failed, with the diplomats and their security guards overwhelmed by the numbers, weaponry and military nature of the attacking force.

American Defense Department officials were too slow to respond when they saw what was happening, charged Berntsen, and didn't send in the troops fast enough.

“They stood, and they watched, and our people died,” he raged. “They made zero adjustments in this. You find a way to make this happen. There isn't a plan for every single engagement. Sometimes you have to be able to make adjustments.”

Sources told CBS there were fighter jets and Specter AC-130 gunships stationed at three nearby bases. But Pentagon officials told reporters the military moved a special ops team from central Europe to Sigonella, Italy instead – an hour's flight from Libya – and refused to provide further details.

A White House source told the network that Defense Secretary Leon Panetta and Chairman of the Joint Chiefs of Staff Martin Dempsey “looked at available options, and the ones we exercised had our military forces arrive in less than 24 hours, well ahead of timelines laid out in established policies.”

By then, the screaming mob of thousands of radical Islamists, whipped into a bloodthirsty frenzy, had torched the cars on the site, torn the building apart, and destroyed the consulate. And four American diplomats were dead.

According to a report published by The New York Times, witnesses have identified Ahmad Abu Khattala as the ringleader of the attack.

But Libyan authorities have not arrested him, nor has he been taken into custody. In fact, he gave the newspaper an interview as he sipped a milkshake on a hotel patio, mocking both the Libyan and U.S. governments.

“Here I am, sitting in a hotel with you,” he pointed out. “I'm even going to pick up my sister's kids from school soon.”

Ambassador Stevens repeatedly noted in communiques to Washington that weak security was an issue at the consulate. He noted in June there had been a spike in attacks against “international organizations and foreign interests,” ABC News reported. In August, he sent a cable warning of a series of violent incidents that “dominated the political landscape during the Ramadan holiday.”

The ambassador underscored to his superiors at the State Department  that the attacks were “organized” and that Libyan security personnel was not a “stabilizing force.” He also noted that the Libyan security force provided “little deterrence” – a major red flag that Washington apparently ignored.

Repeated requests to the Obama administration for additional security to the consulate in Benghazi were rejected.