Chinese authorities have arrested a scholar who helped blind dissident Chen Guangcheng escape house arrest in 2012, the scholar's wife said on Tuesday, in a case that activists say signals a tighter grip on civil liberties.
Guo Yushan, founder of a think-tank that did research on business regulations, reform and civil society, was detained in Beijing in October.
Maya Wang, a researcher at Human Rights Watch, said Guo's detention was "another milestone in the ongoing, severe crackdown on civil liberties" over the past 18 months.