A claim that later was shown to have no evidence to back it up. The fact of the matter is that nobody knows for sure what happened to Cinque once he returned to his homeland.
And your source of information is ........
I've done a little research on Conque's history after his return to Africa. It is more accurate to say that there is no incontrovertible evidence of his activities. Stories were recorded at the time of his slaving activities, but they were more in the nature of rumors. Poor quality evidence, but not no evidence.