Gaddafi Sodomised by Rebels: Shocking Video as new Abuse Claims Emerge [GRAPHIC VIDEO, PHOTOS]

An analysis of a video obtained by GlobalPost from a rebel fighter who recorded Muammar Gaddafi's capture appears to show the former leader being sodomized as he was being dragged from the drainpipe where he had taken refuge.

A frame by frame analysis of the videos clearly shows the rebel trying to insert an object into Gaddafi's rear end.

It is not clear what the object is, but Tracey Shelton, a correspondent for the GlobalPost, said it could either be a knife from the end of a gun, which Libyans call a Bicketti, or a utility tool known as a Becker Knife and Tool, which is popularly known as a BKT.

This latest video discovery comes as international and human rights groups call for a formal investigation into how the former Libyan leader was killed.

A series of graphic videos have appeared since the death of Gaddafi, proving the leader was alive when captured.

While initial reports said the former dictator had been killed in crossfire while en route to hospitals, footage that has appeared since then has shown his body being repeatedly kicked by the Libyan fighters.

Gaddafi was also found with a bullet in his head, raising allegations he had been executed, and in a newly leaked video, a young rebel named Senad el Sadok el Ureybi said he shot the tyrant.

He says on the film: "We grabbed him and I hit him in the face."

"Some of the others wanted to take him away and that's when I shot him, twice -- in the face and chest."

According to the Geneva Convention, abuse of prisoners under any circumstance is not permissible.

Bowing to increasing international pressure, interim leader Mustafa Abdul-Jalil announced Monday that the National Transitional Council had formed a committee to investigate Gaddafi's death.

Rights advocates have called for an independent investigation.

The latest videos come as Human Rights Watch has revealed it had found 53 bodies thought to be Gaddafi sympathisers in a hotel in Sirte, thought to be under the control of NTC fighters when the killings took place.

The rights organisation has also called for an investigations of the crimes committed during the war, whether by Gaddafi or NTC fighters.