Other Russians' mysterious deaths
Renowned journalist Anna Politkovskaya, 48, was fatally shot in the elevator of her Moscow apartment building in October 2006. Her work in the Novaya Gazeta newspaper was sharply critical of Kremlin policies in Chechnya and of human rights violations there. Last year, a court convicted five men, but authorities are still trying to determine who ordered the killing.
Former Russian intelligence officer Alexander Litvinenko, 44, became sick after drinking tea laced with radioactive polonium-210 at a London hotel in November 2006 and died three weeks later. Litvinenko had become a strong critic of the Kremlin. Before he was poisoned, Litvinenko blamed Putin for Politkovskaya's murder. An inquiry in Britain continues.
Human rights activist Natalya Estemirova, 50, was abducted and murdered in Chechnya in July 2009. She exposed alleged abuses by the forces of the Kremlin-backed Chechen president. Russian investigators said that two Islamic militant brothers killed her, but said DNA evidence showed that they did not.