BACKGROUND: Critics of Russian government live in danger

Berlin - The murder on Monday of human-rights activist Zarema Sadulayeva was just one of a series of such assassinations in Russia. While the crimes elicited strong reactions both at home and abroad, many were never resolved. Following is a chronology of prominent murder cases and mysterious deaths during the past six years. July 2009: Human-rights activist Natalya Estemirova is shot dead in Ingushetia, an autonomous republic in Russia's restive North Caucasus. Estemirova, who worked for the organization Memorial in the region, had voiced regular criticism about the disappearance of civilians in neighbouring Chechnya, incurring the wrath of the province's Kremlin-backed leaders. January 2009: Human-rights lawyer Stanislav Markelov and Russian- Ukrainian journalist Anastasia Baburova are shot dead in Moscow in broad daylight. Markelov had in the past worked together with Anna Politkovskaya, a journalist murdered in 2006. Baburova wrote for Novaya Gazeta, an independent newspaper that is regularly critical of the Kremlin. August 2008: Activist Magomed Yevloyev is killed during a police operation in Ingushetia. According to police reports, he was arrested at Nasran airport as part of an ongoing investigation into a bombing and was hit in the temple by a bullet during a scuffle. Yevloyev ran the critical online publication Ingushetiya.ru. November 2006: Former KGB officer Alexander Litvinenko is poisoned and subsequently dies in a London hospital. On his death bed he blames then Russian president Vladimir Putin for the attack. The Kremlin denies the allegation. Litvinenko had been poisoned with radioactive polonium in London. October 2006: Russian journalist and government critic Anna Politkovskaya is shot dead in Moscow. She had reported for Novaya Gazeta from Chechnya on human-rights abuses committed by Russian and local security forces. Her murder is condemned around the world. July 2003: Yuri Shchekochikhin, a member of the Russian Duma, unexpectedly dies. The official cause of death is a cerebral edema. Party colleagues of the liberal politician are convinced that Shchekochikhin, who suffered from a number of allergies, was poisoned with a strong allergen. He had published critical views on Russian conditions in Novaya Gazeta. An investigation is inconclusive.