Last week armed thugs silenced forever an ardent voice for human rights in Russia's North Caucasus region.

Until she was bundled into a van and shot dead last Wednesday, Natalia Estemirova had bravely investigated human rights abuses in the Chechen wars, which often put her in the line of fire.

Estemirova continued her work even as two of her colleagues, lawyer and human rights defender Stanislav Markelov and journalist Anastasia Baburova, were both shot dead in broad day light in January in the center of Moscow for their human rights work. 

The killings of Estemirova and her colleagues are an attempt to gag civil society in Russia. Estemirova's human rights investigations in Chechnya - which included reporting on torture, unlawful killings and enforced disappearances - represented a direct threat to local government and other groups, who in turn intimidated her in vain attempts to shut her up.

Don't let intimidation prevent justice in Russia.  Stand with Amnesty today in demanding a full investigation by Russian authorities into these brutal murders. Only by sending Russian authorities a message from every corner of the global human rights movement can we prevent them from sweeping Estemirova's and other murders under the rug.