of the National Transitional Council, which marked the country's liberation on Sunday in the eastern city of Benghazi, where the uprising started. But uncertainty was still swirling Sunday about the death of the Libyan leader, who Libyan and world powers wanted to capture and prosecute for war crimes. Leaders of Libya's interim government have said Gadhafi was killed in crossfire after fighters captured him Thursday. But others have questioned that account. Peter Bouckaert, Human Rights Watch's emergencies director, told CNN that fighting had ended when Gadhafi was cornered in a drainage ditch. He said crowds beat Gadhafi in what was a humiliating end for the former dictator. When he left the area, he was very much alive, Bouckaert said. There's no reason why he should have been subjected to this kind of mob justice. An amateur video distributed by the Reuters news agency Sunday showed NTC fighters congratulating a man the fighters say killed Gadhafi. CNN could not independently verify that claim. The video, purportedly recorded near an ambulance carrying Gadhafi's body, shows a jubilant group of fighters pouring water on a man's head. He is the one who killed him, one man says, pointing. He killed him in front of me, I swear to God, another man chimes in. A lawyer for Gadhafi's son Saadi, who fled in September to Niger, issued a statement Sunday saying, Saadi Gadhafi is