Excerpted from Reuters:
An ailing Chinese labour activist [Li Wangyang] imprisoned for two decades died in a hospital Wednesday one year after being released from jail, and a relative raised doubt on the official explanation that he had hanged himself. [...]
Li had been a labor activist in the city of Shaoyang in Hunan province, whose advocacy of labor rights during the 1989 pro-democracy protests saw him jailed for 22 years, according to the group Human Rights in China, on charges including counter-revolutionary propaganda and incitement.
For more information on Li Wangyang, see "Relatives Question Hunan Activist’s 'Suicide'; Demand Autopsy."