Vasila Inoyatova, a Tashkent-based human-rights activist, told RFE/RL today that Tojiboeva expressed fears for her life in the letter sent through a prison guard on August 2.
"Tojiboeva wrote she would be killed and asked for help," says Inoyatova.
In the letter, which RFE/RL has acquired a copy of, Tojiboeva also named the prison guards who tortured her.
Tojiboeva, who headed the unregistered Otyuraklar (Fierce Hearts) human-rights group in the eastern Uzbek city of Margilon, was also a Nobel Peace Prize nominee.
The Dublin-based Front Line, an organization that helps human-rights defenders around the world, has expressed "grave concern" over Tojiboeva’s detention and reproted deteriorating health.
The activist was detained in October 2005, just ahead of a human-rights conference she was scheduled to attend in Dublin.
Tojiboeva was subsequently sentenced to eight years in prison in March 2006.
She has been held in a solitary confinement in a prison near Tashkent and reportedly denied medical care despite deteriorating health. Her family has not been allowed to visit her since January.