Conversation so far:
who was punished for the my lai massacre
Lieutenant William Calley Jr., a platoon leader in C Company, was convicted for the My Lai massacre.
was anyone else besides Lieutenant William Calley Jr. convicted for the My Lai massacre.
Twenty-six soldiers were charged with criminal offenses, but only Lieutenant William Calley Jr. was convicted.

Question: what was the sentence
Self-contained rewrite: what was Lieutenant William Calley Jr.'s sentence for the my lai massacre