The Libyan ruling National Transitional Council (NTC) said Thursday that whoever killed ex- leader Muammar Gaddafi will be put on trial.

The Libyan authorities have already started investigations on the death of Gaddafi, Abdel Hafiz Ghoga, vice chairman of the NTC, said at a press conference held in Libya's second largest city Benghazi, adding that they have "the code of ethics" concerning how to deal with war criminals.

Whoever killed Gaddafi "will be brought to justice," said Ghoga, who announced on Oct. 23 the "liberation" of the entire Libya after all pro-Gaddafi strongholds had fallen into NTC's control.

Gaddafi "mysteriously" died shortly after he was captured alive a week ago in his hometown of Sirte in northern Libya, before his corpse was transferred to Misrata, some 200 km east of the capital Tripoli, where it had been on public display for almost five days.

The NTC leaders have said following Gaddafi's death that he was killed in the crossfire between his loyalists and the NTC fighters after his capture.

But rumors have been circulating that he was intentionally shot dead by the NTC fighters, ahead of the international calls for the NTC to carry out a thorough investigation into the circumstances of the death of the iron-handed leader of the country for over four decades, who was driven out of the capital in late August.

On Thursday in Benghazi, Ghoga stressed that (if Gaddafi is proved to have been killed by NTC fighters), it must be "an individual act."

NTC Chairman Mustafa Abdel Jalil said Monday that a committee would be set up soon to investigate Gaddafi's death, a day before Gaddafi and his son Mutassim were buried early Tuesday morning at a secret location in the desert.