* Bodyguard's grenade bounced back, ended escape bid
* U.N. commission finds no firm evidence on how he died
* Team says murder, pillage continue in Libya
By Robert Evans
GENEVA (Reuters) - Long-time Libyan leader Muammar Gaddafi, stranded in the desert after rebels and a NATO missile strike wrecked his escape convoy last October, apparently wanted to stage a last stand as his enemies closed in, a U.N. report said on Friday.
His son Mutassim and aides persuaded him to try to get away but as they crawled on their bellies through the sand, power lines from a damaged transformer fell on his head and he was wounded by a misdirected grenade thrown by one of his own men.
The dramatic account of the last hours of the life of the man who had ruled the north African nation for four decades, came from an international commission of inquiry set up in March last year soon after an uprising against him began.
Isolated with a few men in a house with rebels all around, their report said, "Muammar Gaddafi reportedly wanted to stay and fight, but was persuaded to escape."
The 200-page report for the U.N.'s Human Rights Council, now holding its spring session, was released by officials of the world body in Geneva in an unedited version, but is due for discussion in the next three weeks.
The commission, led by Canadian jurist Philippe Kirsch, found that in the fighting that rolled back and forth across Libya in 2011, both sides committed war crimes, including murder and torture.
While Gaddafi's forces also committed "international crimes against humanity...in the context of a widespread or systematic attack against a civilian population," the team said, killing, torture and pillage were continuing under the new authorities.
But they said "current conditions" in Libya had to be understood against the background of "the damage caused to the fabric of the society by decades of corruption, serious human rights violations and sustained repression of any opposition."
Scenes of the rebels' capture of Gaddafi, wounded and apparently disorientated, and his son on October 20 just outside his home town of Sirte, filmed on a mobile phone, were seen around the world at the end of last year.
The inquiry team said it had not been able to obtain a first-hand account of how he died - some accounts said he was shot in the head by a rebel fighter in an ambulance - and had only "inconsistent accounts from secondary sources."
For this reason, the team said, it had been "unable to confirm the death of Muammar Gaddafi as an unlawful killing and considers that further investigation is required."
His body was buried in a secret desert location on the orders of the National Transitional Council, which now forms the government and argues that this was necessary to prevent his grave from becoming a shrine.
The three-member team said they wrote their account after extensive questioning of witnesses who had been on both sides in the conflict.
Mutassim Gaddafi decided on October 19 to break out from Sirte as rebel forces moved into the coastal city, and the next day they set off in a heavily armoured convoy of 20 vehicles with 200 armed men, and some women and children, the report said.
Running into a rebel ambush, the battered convoy circled onto a coast road and split up. But a vehicle just in front of the green four-wheel-drive vehicle in which Gaddafi was travelling was hit by a NATO missile and blew up.
The explosion set off air bags in Gaddafi's car and, under fire from rebels, he, his son and defence minister Abubakr Younis took shelter in a nearby house, which was then shelled by the rebels.
Mutassim then took some 20 fighters and went to look for undamaged cars, having persuaded his father to come too. "The group belly-crawled to a sand berm," the report said, and then through two drainage pipes and set up a defensive position.
One of Gaddafi's guards threw a grenade at advancing rebels on the road above but it hit a cement wall above the pipes and fell in front of Gaddafi. The guard tried to pick it up, but it exploded, killing him and Younis.
"Gaddafi was wounded by grenade shrapnel that shredded his flak jacket. He sat on the floor dazed and in shock, bleeding from a wound in the left temple," the report said. Then one of his group waved a white turban in surrender.
Reported by Robert Evans; Editing by Tim Pearce