Conversation so far:
Who captured Zheng He?
Ma He was captured by the Ming armies at Yunnan in 1381.
When was he captured?
in 1381.
Why was he captured?
Ma He responded defiantly by saying that the Mongol pretender had jumped into a lake.
Afterwards, the general took him prisoner.
How old was he when captured?
CANNOTANSWER.

Question: What did they do to him while in captivity?
Self-contained rewrite: What did the Ming armies do to Zheng-He while in captivity in 1381?