Final answer:
The men who were taken from Guinea to Portugal and then returned to their homeland were killed by their tribesmen as traitors.
Step-by-step explanation:
According to Columbus, the men who were taken from Guinea to Portugal and then returned to their homeland were killed by their tribesmen as traitors. this happened because the Africans who were captured and returned were seen as traitors for collaborating with the Portuguese colonizers. This is supported by the fact that many African kingdoms resisted the growing trade in enslaved people as tensions rose among African polities.