The authors of the appeal ask Medvedev to instruct the Prosecutor General’s office to take measures.

In their opinion, “Unbiased investigation of Estemirova’s murder by the local law-enforcement officials is impossible, as it was also them who used to be mentioned by Natalya Estemirova in her materials on human rights violations.”

“The same as you, we believe that this murder has a connection with Estemirova’s professional activity in the human rights field,” the authors wrote to Medvedev.

Because Estemirova, like lawyer Stanislav Markelov and journalist Anna Politkovskaya,– were working to protect human rights in situations involving state officials as suspects, the latter were obviously interested in stopping them from unveiling human rights violations, the letter says.

Friends, colleagues and hundreds of other people gathered on Thursday to remember Estemirova, who was an outspoken critic of the Chechen authorities over human rights abuses.

They held a rally in the center of Moscow nine days after the activist was killed, and called on the authorities to bring to justice those behind the killing.

Estemirova was kidnapped last week in Russia's Republic of Chechnya in the Northern Caucasus, and her body was later found in neighboring Ingushetia.