OMFG someone like you. With your logic. If the Africans captured them, what did the do with them? OH YEAH!! They sold them to the Europeans who DEMANDED the slaves.
You are seriously hopeless. For the reason I posted, saying that there was SLAVES IN AFRICA (maybe capitalization helps you). But slavery pre-Atlantic Slave Trade or European arrival was same as Europe. Mainly indentured servants, people captured in war, etc.