Beirut, Lebanon (CNN) -- Over the past month, video has emerged from the Syrian city of Homs showing killings and other atrocities apparently committed by security forces in neighborhoods that have opposed the government.
CNN has obtained footage that is among the most disturbing yet -- about a dozen family members killed in one house in what appears to be sectarian brutality.
CNN is confident of the video's provenance. The images show a group of nine men crouched as they move across rooftops, then crawl through a hole smashed in a wall to reach a house on a sectarian fault line that runs through Homs.
"We're rescuing the bodies of the martyrs," a man's voice says on the video.
About a week earlier, the men received information that a Sunni family had been killed, but it took them this long to launch their mission.
When they reach the house, they come across a grisly find: the body of a woman lying face down on the carpet.
In an adjacent room, they find more bodies next to each other in a corner, as though they had been trying to hide. One of them, a child, lays with his face frozen in fear, mouth open and arms outstretched.
On his chest leans another body, its head covered in a khaki-colored cloth. A third body, with its head covered in a black cloth, leans against the second.
Beside the pile of bodies, about a foot above the slumped third body, the white wall is splattered red.
"Let the world see," a voice exclaims on the video. "Look at this massacre in just one house."
The man curses the Shias, the Alawites and President Bashar al-Assad. Syria is a nation with a Sunni majority governed by a minority Alawite, an offshoot sect of Shia Islam.
The video is said to have been shot in the neighborhood of Sabeel last month.
"Oh, look, people, look," says one man, overcome with emotion as he too curses the regime -- and the world.
The camera pans to show more bodies in the bathroom. Suddenly, from another floor, a whimper.
The men are stunned, and coax a child out of a dark room where he must have been hiding for days.
The child, in a red, hooded sweatshirt, comes into view, crawling over a body in the doorway to reach the men, who greet him with open arms.
The men say they do not know who killed the boy's family or why.
But they do know, they say, that the killings were a sectarian massacre carried out by thugs allied to the regime.
CNN has attempted to reach the Syrian Foreign Ministry for reaction but there was no answer. The Syrian government has in the past blamed armed gangs for such attacks.