Human rights organisations have cast doubt on claims of mass rape and other abuses perpetrated by forces loyal to Colonel Muammar Gaddafi, which have been widely used to justify Nato's war in Libya.
Nato leaders, opposition groups and the media have produced a stream of stories since February 15 claiming the Gaddafi regime has ordered mass rapes, used foreign mercenaries and employed helicopters against civilian protesters.
An investigation by Amnesty International has failed to find evidence for these human rights violations and in many cases has discredited or cast doubt on them.
It also found indications that on several occasions Benghazi rebels appeared to have knowingly made false claims or manufactured evidence.
The findings appear to be at odds with the views of the prosecutor of the International Criminal Court, Luis Moreno-Ocampo, who two weeks ago said "we have information that there was a policy to rape in Libya those who were against the government. Apparently he [Colonel Gaddafi] used it to punish people".
United States Secretary of State Hillary Clinton said last week she was deeply concerned that Gaddafi's troops were participating in widespread rape. "Rape, physical intimidation, sexual harassment and even so-called virginity tests have taken place in countries throughout the region," she said.
Donatella Rovera, senior crisis response adviser for Amnesty, who was in Libya for three months after the start of the uprising, said "we have not found any evidence or a single victim of rape or a doctor who knew about somebody being raped".
She stresses this does not prove mass rape did not occur but there is no evidence to show that it did.
Liesel Gerntholtz, the head of women's rights at Human Rights Watch, which also investigated the charge of mass rape, said: "We have not been able to find evidence."
In one instance two captured pro-Gaddafi soldiers presented to the international media by the rebels claimed their officers, and later themselves, had raped a family with four daughters. Rovera says when she and a colleague interviewed the two detainees, aged 17 and 21, alone and in separate rooms, they gave differing accounts.
"They both said they had not participated in the rape and just heard about it," she said. "They told different stories about whether or not the girls' hands were tied, whether their parents were present and how they were dressed."
The strongest evidence for mass rape appeared to come from a Libyan psychologist, Seham Sergewa, who says she distributed 70,000 questionnaires in rebel-controlled areas and along the Tunisian border, of which more than 60,000 were returned.
About 259 women volunteered that they had been raped, of whom Sergewa said she interviewed 140.
Asked by Diana Eltahawy, Amnesty International's specialist on Libya, if it would be possible to meet any victims, Sergewa said "she had lost contact with them" and couldn't provide documentary evidence.
The accusation that Viagra had been distributed to Gaddafi's troops to encourage them to rape women in rebel areas first surfaced in March after Nato destroyed tanks advancing on Benghazi. Rovera says rebels started showing journalists packets of Viagra, claiming they came from burned-out tanks, though it is unclear why the packets were not charred.
Credible evidence of rape came when Eman al-Obeidi burst into a hotel in Tripoli on March 26 to tell journalists she had been gang-raped before being dragged away by the Libyan security services.
Rebels have repeatedly charged that mercenary troops from Central and West Africa have been used against them. Amnesty found there was no evidence for this.
"Those shown to journalists as foreign mercenaries were later quietly released," says Rovera. "Most were sub-Saharan migrants working in Libya without documents."
Others were not so lucky and were lynched or executed. Rovera found two bodies of migrants in the Benghazi morgue and others were dumped on the outskirts of the city.
She says: "The politicians kept talking about mercenaries, which inflamed public opinion and the myth has continued because they were released without publicity."
Nato intervention started on March 19 with air attacks to protect people in Benghazi from massacre by advancing pro-Gaddafi troops. There is no doubt civilians did expect to be killed after threats of vengeance from Gaddafi. During the first days of the uprising security forces shot and killed demonstrators and people attending their funerals, but there is no proof of mass killing of civilians on the scale of Syria or Yemen.
Most of the fighting during the first days of the uprising was in Benghazi, where 100 to 110 people were killed, and the city of Baida, where 59 to 64 were killed, says Amnesty. Most of these were probably protesters, though some may have obtained weapons.
Amateur videos show some captured Gaddafi supporters being shot dead and eight badly charred bodies were found in the remains of the military headquarters in Benghazi, which may be those of local boys who had disappeared.
There is no evidence that aircraft or heavy anti-aircraft machine guns were used against crowds. Spent cartridges picked up after protesters were shot at came from Kalashnikovs or similar calibre weapons.
The Amnesty findings confirm a report by the authoritative International Crisis Group, which found that although the regime had a history of brutal repression, there was no question of genocide.
It adds that "much Western media coverage has from the outset presented a very one-sided view of the logic of events, portraying the protest movement as entirely peaceful and repeatedly suggesting the regime's security forces were unaccountably massacring unarmed demonstrators who presented no security challenge".
By Patrick Cockburn