“There’s a lot of uncertainty about what happened exactly. There seem to be four or five different versions of how he died,” UNCHR spokesman Rupert Colville told Reuters Television in an interview.
“If you take these two videos together, they are rather disturbing because you see someone who has been captured alive and then you see the same person dead.
“We are not in a position to say what happened at this point but we feel that it is very important that this is clarified, that there is some sort of serious investigation into what happened and what caused his death,” he said.
Asked whether the office of the UNCHR commissioner Navi Pillay was concerned Gaddafi may have been executed while in captivity, Colville replied:
“It has to be one possibility when you look at these two videos. So that’s something that an investigation needs to look into,” he said.
Gaddafi was fatally wounded by a bullet in his intestines following his capture, according to a doctor who examined his body, amid conflicting accounts of how the fugitive former Libyan leader met his end at the end of an eight-month uprising against his 42-year rule.
“Gaddafi was arrested while he was alive but he was killed later. There was a bullet and that was the primary reason for his death, it penetrated his gut,” doctor Ibrahim Tika told Al Arabiya television. “Then there was another bullet in the head that went in and out of his head.”
Earlier, Prime Minister Mahmoud Jibril, reading what he said was a post-mortem report, said Gaddafi was hauled unresisting from a “sewage pipe”, shot in the arm and put in a truck which was “caught in crossfire” as it ferried him to hospital.