Labeled the work of Fahd al-Bakkosh, the video centers on what appears to be the same tall, narrow window that witnesses have described as Mr. Stevens’s last exit. The witnesses said residents drawn to the scene had forced open the window and found Mr. Stevens behind a locked iron gate, pulled him out and taken him to the hospital. In the video, none say anything that shows ill will.

“I swear, he’s dead,” one Libyan says, peering in.

“Bring him out, man! Bring him out,” another says.

“The man is alive. Move out of the way,” others shout. “Just bring him out, man.”

“Move, move, he is still alive!”

“Alive, Alive! God is great,” the crowd erupts, while someone calls to bring Mr. Stevens to a car.

Mr. Stevens was taken to a hospital, where a doctor tried to revive him, but said he was all but dead on arrival.