The one-minute video, which has circulated on dozens of mobile phones in Port Salut, pans out from a sideways close-up of the alleged victim's strained face to reveal his body being held down on a mattress by light-skinned men wearing camouflage-coloured clothes.
Some of them are seen wearing sky-blue caps in the style of those worn by UN peacekeeping forces. As the men's laughter grows in volume, a shirtless soldier kneels behind the man, slaps him and appears to thrust towards him.
The video ends as the bedraggled young man is grabbed by the arm and pulled onto his feet.
Nabaa said the UN inquiry had not yet proven the video's authenticity, but that "the results of the investigation will determine the facts".
FranzDG is Comic-book Illustrator / Graphic Artist with a fine arts background based in Los Angeles. He worked for several studios as a professional comic-book illustrator and had multiple art exhibitions in his spare time. Currently working as a illustrator/graphic artist for clothing companies Arm the Animals and popKiller.