The brother of Chinese dissident human rights lawyer Gao Zhisheng has told two news agencies that his brother is now in a Xinjiang prison, being the first confirmation of his whereabouts in 20 months.

Gao Zhiyi added that he received a notice last Sunday informing him that his brother was back in prison because a court had revoked his probation, and that he would have to serve a further three years. Chinese state media reported last month that he had violated his probation.

In 2006 Gao Zhisheng was sentenced to three years’ imprisonment for “subversion of state power”, having defended the rights of political and religious dissenters such as the Falun Gong, an outlawed spiritual sect in China. Since 2009 he has largely been held incommunicado. In the same year he was taken from a relative’s home in Shaanxi province, northern China, resurfacing briefly in March 2010, when he told the Associated Press he had been tortured. He disappeared again soon after.

Gao’s case is one of the most high-profile abuses of human rights in China, drawing widespread condemnation from the international community and calls for his release.