As the charred skeletons of more than 50 people are found in a farm building outside Tripoli, Chief Correspondent Alex Thomson tracks the terrifying ordeal of black Africans caught up in the war.
Warning: You may find some of the details in this report distressing.
Amnesty International says it has evidence that 31 prisoners were executed by pro-Gaddafi forces at two military camps in Khilit al-Ferjan and Qasr Ben Ghashir.
Human Rights Watch says 18 bullet-ridden bodies were discovered near the Gaddafi stronghold of Bab al-Aziziya, two with hands tied. Nearby 29 corpses were also found showing signs of execution.
At Salaheddin near the base of the feared Khamis brigade, Channel 4 News Chief Correspondent Alex Thomson witnessed the place where at least 50 people were killed five days ago.
It is not clear why these people were rounded up. Local residents discovered the skeletons after rebels took control of Brigade 32.
On the road opposite the base three suspected mercenaries were arrested. Rebels brought them inside the building which they have now taken over as a command centre. The suspects said they were on their way to Italy.
Mohammed Ayoun, a rebel who had come from Mistrata, said they would be taken to a special council set up to deal with suspected mercenaries.
But Channel 4 News spoke to a group of black Africans who denied they were mercenaries. They said they were workers trying to get to Europe now fearing for their lives.
The men, clearly terrified and some weeping, said: “Please don’t go. Don’t leave us. They will kill us.”
Chief Correspondent Alex Thomson blogs from Libya:
We'd barely got through the imposing entrance to Khamis army base in southern Tripoli when all hell broke loose.
Suddenly armed anti-Gaddafi fighters appeared, shoving and hitting nine black men into the guard post at the main gate.
Read more: Caught up in someone else's war
Foreign Secretary William Hague has called an offer of fresh talks with rebel forces by Colonel Gaddafi “delusional”. Mr Hague told Sky News that the time for dialogue had clearly now passed. Last week the colonel labelled opposition forces “rats”.
Mr Hague said: “The transition is taking place, Gaddafi should now tell his remaining forces to lay down their arms so that others can take Libya forward to a peaceful future.”
Meanwhile, a minister in Libya’s National Transitional Council (NTC) has said that Libya will not extradite Abdel Basset al-Megrahi, the man convicted of the 1988 Lockerbie airline bombing.
“We will not give any Libyan citizen to the west,” Mohammed al-Alagi, the NTC justice minister, told reporters in Tripoli.
“Al-Megrahi has already been judged once and he will not be judged again … We do not hand over Libyan citizens, Gaddafi does.”