(CNN) -- A second Syrian teenager has been returned to his parents -- lifeless, battered and, according to activists, a victim of torture.

A video released Thursday by activists includes a woman wailing as a body is unwrapped at the hospital in Daraa.

"My son, it's my son," the voice cries out. "This scar here, I swear its my son, I stitched this cut on him when he was little."

The boy was identified as Tamer Mohammed al Sharey, 15, who disappeared after an April 29 demonstration.

He was from the same village as Hamza Ali al-Khateeb, 13. Hamza's killing has enraged, mobilized and emboldened the country's opposition movement. Tamer was at the same demonstration Hamza attended, according to activists.

Tamer's body was one of 14, including those of other children, that arrived at the hospital.

In the video, voices curse Syrian President Bashar al-Assad. As several men clean Tamer's thin frame, a bullet wound beneath the knee is clearly visible.

As the camera moves to his head, a voice says, "look at the signs of torture."

The teen's face appears dark and discolored. An activist from Daraa told of marks on the boy's body. He said he believes Tamer was tortured, possibly electrocuted.

Children led Tamer's funeral procession carrying banners reading, "Tamer the martyred ... detained alive ... martyred after torture."

CNN cannot independently verify what happened to Hamza or Tamer, or verify the authenticity of videos allegedly showing their remains.

On a video posted on YouTube, the narrator points out multiple visible gunshots wounds to Hamza Ali al-Khateeb's torso. His head appears bloated and purple, and the voice says the teen's genitals were mutilated.

Family members say Hamza got separated from his father in the chaos during demonstrations around Daraa, when protesters marched on the city to break the Syrian military siege and force the delivery of important supplies, such as medicine and milk for babies.

Eyewitnesses at the time said that security forces indiscriminately opened fire on demonstrators. Dozens were killed and wounded, countless others detained, among them children.

Several weeks ago, the family received Hamza's body.

Razan Zaitouneh, a prominent activist in hiding in Syria who CNN reached via Skype, said she has no doubt that the YouTube video of Hamza is real. And she believes that the regime had a message in releasing the boy's body.

"They want the people to see this, they want the people to get scared," Zaitouneh said. "They want the people to know that there is no red line and anything, no matter how awful it is, could happen to their family members if they continue to participate in this revolution."

Syrian state TV recently ran a segment in which a person identified as the medical examiner in the case said the body's injuries were sustained when Hamza was alive, but there was no evidence on the surface of the body that the boy had been subjected to torture, violence or retaliation.

Syria TV also said al-Assad met with members of Hamza's family.

CNN's Salma Abdelaziz contributed to this report.