The Migration and Law NGO reports on its website Svetlana Martynova's 22-year-old son was found dead in the central Russian city of Ivanovo on September 14.
Authorities say Aleksandr Martynov died of an overdose. However, Martynova claims her son never took any drugs.
She says her son's face was so swollen and covered with bruises that she hardly recognized him.
One Kyrgyz and 12 Uzbek nationals have been awaiting extradition in an Ivanovo prison cell. Uzbekistan accuses them of helping organize antigovernment protests in Andijon in May 2005.
The Russian Prosecutor-General's Office last month ruled that they should be deported to Uzbekistan. It later suspended the procedure pending a ruling by the European Court of Human Rights.