Story highlights U.S. Ambassador Chris Stevens and 3 others were killed last Tuesday in Libya

A video shows a wounded "foreigner" dragged from a window that night

The man who shot the video says it's Stevens; a U.S. official says they're not sure

The Libyans rejoice when they discover the man is alive and try to get him help

The chaos is palpable, as a throng of Libyans frantically scramble outside a damaged building. Suddenly, a man's body is carried from inside toward an open window -- and the frenzy and sounds become even more urgent, more emotional.

"Get him out!" some yell.

After joyfully discovering the man -- a foreigner, apparently, a voice in the crowd says -- is alive after he's dragged out, fresh screams ring out.

"Allahu Akbar," which translates from Arabic to "God is great," men in the crowd shout. Others raise fists to the sky, seemingly rejoicing that this man has somehow survived.

According to the man who shot the video, the wounded man shown is Chris Stevens , the late U.S. ambassador to Libya. If true, the grainy images show some of his last moments alive: Stevens was one of four Americans killed last Tuesday in an attack on the U.S. consulate in Benghazi, Libya.

U.S. State Department spokeswoman Victoria Nuland acknowledged the video Monday, even as she stressed it's not clear "whether or not it's authentic, whether or not it is an accurate representation of what happened, whether or not it's Ambassador Stevens."

Photos: Photos: Attack on U.S. mission in Benghazi Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Attackers set the U.S. mission in Benghazi, Libya, on fire on September 11, 2012. The U.S. ambassador to Libya, Christopher Stevens, and three other U.S. nationals were killed during the attack. The Obama administration initially thought the attack was carried out by an angry mob responding to a video, made in the United States, that mocked Islam and the Prophet Mohammed. But the storming of the mission was later determined to have been a terrorist attack. Hide Caption 1 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Obama and Clinton stand at Andrews Air Force Base as the bodies of the four Americans killed are returned on September 14. Hide Caption 2 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A desk sits inside the burnt U.S. mission on September 13, two days after the attack. Hide Caption 3 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Damage is seen inside the U.S. mission on September 13. Hide Caption 4 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A lounge chair and umbrella float in the swimming pool of the U.S. mission on September 13. Hide Caption 5 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Demonstrators gather in Libya on September 12 to condemn the killers and voice support for the victims. Hide Caption 6 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – U.S. President Barack Obama, with Secretary of State Hillary Clinton on September 12, makes a statement at the White House about Stevens' death. Hide Caption 7 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A burnt vehicle is seen at the U.S. mission in Benghazi on September 12. Hide Caption 8 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – People inspect the damage on September 12. Hide Caption 9 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A small American flag is seen in the rubble on September 12. Hide Caption 10 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A man stands in part of a burned-out building of the U.S. mission on September 12. Hide Caption 11 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Smoke and fire damage is evident inside a building on September 12. Hide Caption 12 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Half-burnt debris and ash cover the floor of one of the U.S. mission buildings on September 12. Hide Caption 13 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – The U.S. mission is seen in flames on September 11, the day of the attack. Hide Caption 14 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A protester reacts as the U.S. mission burns on September 11. Hide Caption 15 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A vehicle and the surrounding area are engulfed in flames on September 11. Hide Caption 16 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Flames erupt outside of a building on September 11. Hide Caption 17 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A vehicle burns during the attack on the U.S. mission on September 11. Hide Caption 18 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Onlookers record the damage from the attack on September 11. Hide Caption 19 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – Onlookers walk past a burning truck and building on September 11. Hide Caption 20 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – A vehicle sits smoldering in flames on September 11. Hide Caption 21 of 22 Photos: Photos: Attack on U.S. mission in Benghazi Attack on U.S. mission in Benghazi – People duck flames outside a building on September 11. Hide Caption 22 of 22

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"This video ... is going to be part and parcel of this investigation," Nuland told reporters. "But I'm not in a position to confirm what, who, where and whether it has any value."

That investigation will try to explain who is responsible, and what happened, the night of September 11 outside the U.S. consulate.

A strident crowd had gathered there, ostensibly to rail against the United States -- like Egyptian protesters were also doing about 780 miles (1250 kilometers) east in Cairo -- over the 14-minute trailer of an obscure, amateurishly and privately produced film mocking the Muslim prophet Mohammed.

Some of those in Benghazi eventually attacked the consulate, with Libyan and U.S. officials offering differing assessments on whether this assault was spontaneous or premeditated.

What is obvious is that, once they were done, the consulate was charred and heavily damaged, its walls blackened with smoke and its contents largely unrecognizable.

The man who shot the aforementioned video, Fahed al-Bakush, told CNN he'd arrived shortly before midnight to find the consulate cafeteria building up in flames.

The smoke was so thick, he said, that you could barely see the consulate's main building.

Yet the video shows lots of activity, especially near an open window. People clambered in and out of it, aided by small flashlights and each other.

Eventually, the wounded man was carried out. Afterward, he's pictured on the ground in what appears to be a shirt and dark pants.

"He had a pulse and his eyes were moving," al-Bakush said of the man he said is Stevens. "His mouth was black from all the smoke."

With the man now outside, some yelled out," Carry him," and others said, "We need to take him ... to the hospital." A later photo, also seen online, showed the wounded man being put on another man's shoulder and whisked away.

By the time he arrived at a Benghazi hospital, it was too late.

"The body was covered with soot," said Dr. Ziad Abu, who treated Stevens that night. "I began resuscitation but after 45 minutes, the patient ... showed no signs of life."

Many questions remain about the attack that led to Stevens' death.

But if this video indeed shows the ambassador being taken from the consulate, as people thank God that he was breathing and tried to rush him to get medical help, it indicates that not everyone in Benghazi was bent on violence that night.

In fact, it appears that some men -- as evidenced by their words and actions -- were helping him, and very much wanted him to live.