Pavel Kushnir had protested repeatedly against Russia’s invasion of Ukraine, and began a hunger strike soon after his arrest in May, later refusing water too.
He died, slowly and without publicity, on 28 July - four days before a group of better-known dissidents were swapped for Kremlin spies, sleeper agents and killers imprisoned in the West.
After his lonely death, at a pre-trial detention centre in Birobidzhan in Russia’s Far East, the 39-year-old was mourned by only 11 people at his cremation.
Svetlana Kaverzina, an independent politician in Siberia, said no-one had tried to talk him out of sacrificing himself because they hadn’t been aware what was happening.
"We couldn’t chip in and send him a lawyer - we didn’t know," she wrote on the Telegram messaging app. "He was alone."