Duvanov was arrested in October 2002 at his datcha outside Almaty, accused of raping a 14-year old girl, one day before a planned trip to the United States, where he was due to talk about Kazakhstan's human rights situation.
In January 2003 he was found guilty of the crime and sentenced to 3 1/2 years in prison.
Duvanov and the opposition claim that the case was politically motivated.