Conversation so far:
Why was Ken Saro-Wiwa arrested?
Ken Saro-Wiwa was arrested and accused of incitement.
Was Ken Saro-Wiwa placed in jail?
Ken Saro-Wiwa was imprisoned for over a year.
How was Ken Saro-Wiwa executed?
Ken Saro-Wiwa was executed by hanging by a team of executioners flown in from Sokoto.

Question: What year was he executed?
Self-contained rewrite: What year was Saro-Wiwa executed?