Good that you reminded me of it.
In the start of the revolution, Gedaffi sent a couple of thousand mercenaries to Benghazi to suppress the revolution. These mercenaries were mostly black or negroid people, at this point, Gedaffi still hadn't started recruiting mercenaries from other African countries, but he recruited African immigrants mostly from the South to fight for him. Also another thing that should be noted is, Gedaffi recruiting Africans is not recent, he started doing this in the 80's after he split up the Libyan army(he was scared of them becoming too powerful) from then he used to bring in Africans, put them in military bases, indoctrinate them and train them to fight, these Africans were given the Libyan nationality. The result was that Libya didn't have a real organized army, it had separate battalions that consisted mostly of Africans, but the Africans were all fighters, the officers, commanders etc were all Libyan.
So anyway, he sent a huge number of Africans, some of them with actual African nationalities and others were the ones i referred to above, with Libyan nationalities. One thing you have to know about Benghazi is, this revolution was expected, they attempted a similar one in 2009 and one more well known in 2006, where over 50 were killed. So when the Arab spring started, Gedaffi knew all along this was coming. He had plans ready to send in mercenaries to Benghazi and suppress it harder than he did in 2009 and 2006. He knew there will be more people protesting, but what you have to understand is that in 2006 the estimates were a couple of thousand went out to protest, in 2009 it didn't even reach a thousand, so Gedaffi expected maybe 7-8k at most. Instead tens of thousands took the streets in 17th february, even more in the 18th and more in the 19th, more than half of Benghazi was out in the streets, in the first few days the mercenaries did unspeakable things, from killing to rape, to stealing, to torturing the ones they arrested. People were absolutely boiling, and when the 19th came, and tens of thousands took the streets, their goal was one thing and one thing only, hunt down the mercenaries one after the other. Terrible things happened, they outnumbered the mercenaries, and there were lots of cases where they'd catch a mercenary, some would try to arrest him, while the vast majority couldn't control themselves and they'd be beaten to death. In some cases they'd catch them, and hang them over a high building, some were shot at after they were did, some were decapitated, horrible, horrible stuff happened in the first few days in both Benghazi and Misrata.
After that, the transitional national council was formed, and now the rebels had someone to represent them, of course the transitional national council wanted to be recognized as the official representative of the people. The first thing they did was to try and organize the rebels, instead of thousands of angry people taking the streets with sticks, knives, ropes and stuff like that, they wanted to make an army. When the transitional national council was formed, there was a lot of defection from army personnel, which made the rebels have open access to weapons and such. Anyway, the transitional council forbid the sort of things that were happening to the mercenaries, and those heinous things that were happening to the mercenaries in the first few days were stopped.
Still, black Africans, and black Libyans of African origin were then employed everywhere in Libya. But discriminatory cases against blacks never reached the height of killing or torture after a few days. What did happen in a few cities, was that many blacks were wrongly assumed to be fighting with Gedaffi, and arrested for nothing, but thats as far as it went later on in the revolution.