Complex sentence: After helping a friend on the run from the authorities, he was imprisoned and died in Toyotama Prison 40 days after the war ended, on September 26 1945 "Miki Kiyoshi", Encyclopedia Britannica due to an illness resulting from poor prison conditions.
Split into simpler sentences: After helping a friend on the run from the authorities, he was imprisoned. Miki died in prison on September 26,1945 due to an illness resulting from poor prison conditions.