A post-mortem examination on the body of Libya's ex-leader Muammar Gaddafi has been performed in Misrata, an official told the BBC. He said the body would be handed over to relatives. The burial has been delayed, with officials divided about what to do with the body. The UN and the family have called for a full investigation into his death. Video footage showed Col Gaddafi alive after his capture in Sirte on Thursday, and then dead a short time later. The US has called on Libya's new authorities to give a full account of Col Gaddafi's death in an "open and transparent manner". Libya's National Transitional Council (NTC) is expected to formally announce the liberation of the country during the weekend. Election date The first elections should take place by next June, Libya's acting prime minister has said. "According to what we call the constitutional declaration, the first election after the liberation of the country... should be within a period of eight months maximum," Mahmoud Jibril told a conference in Jordan. "The national congress of Libya... is entitled with two tasks, the first one to draft a constitution over which we'll have a referendum and the second task is to form the interim government which should last until the first presidential elections are held." Meanwhile, Nato says it will end its campaign in Libya by 31 October. The alliance's Secretary General, Anders Fogh Rasmussen, said that as the mission wound down, Nato "will make sure there are no attacks against civilians during the transition period". Nato's seven-month campaign of air strikes was carried out under a UN mandate authorising the use of force to protect civilians in Libya. Body in freezer Hundreds of Libyans had been queuing to get a glimpse of the body of Col Gaddafi in a meat storage room in Misrata. The BBC's Gabriel Gatehouse in the city says some - mostly women - craned their necks to see the body of his son Mutassim, who was also killed on Thursday. Officials, including acting Prime Minister Mahmoud Jibril, have also been to see the corpses. It is unclear whether the ex-leader will be buried in Misrata, in his hometown of Sirte, or elsewhere. Officials from the NTC had earlier said they would conduct a secret burial to prevent any grave being turned into a shrine. 'Major concerns' Meanwhile, questions are mounting as to exactly what happened in Col Gaddafi's last moments following his capture. Mr Jibril said Col Gaddafi had been shot in the head in an exchange of fire between Gaddafi loyalists and NTC fighters in Sirte. Video footage suggests he was dragged through the streets. In Washington, state department spokesman Mark Toner said the NTC "has already been working to determine the precise cause and circumstances of Gaddafi's death, and we obviously urge them to do so in an open and transparent manner as we move forward". But Russia's Foreign Minister Sergei Lavrov said the "way his death happened poses an entire number of questions". Mr Lavrov called for a full investigation, echoing a similar call by UN Human Rights Commissioner Navi Pillay. Her spokesman Rupert Colville told the BBC that the killing could have been illegal. "There are two videos out there, one showing him alive and one showing him dead and there are four or five different versions of what happened in between those two cell phone videos. That obviously raises very, very major concerns," he said. However, correspondents say few Libyans are worried about the manner of their former dictator's humiliating end. Celebrations continued late into the night across Libya. Col Gaddafi, who came to power in a coup in 1969, was toppled in August. He was making his last stand in Sirte alongside two of his sons, Mutassim and Saif al-Islam, according to reports. There are conflicting reports as to the whereabouts of Saif al-Islam, and Col Gaddafi's security chief - who are both at large.