The arrest of journalist Gao Yu is the latest in a string of detentions that critics say shows Chinese leaders‘ sensitivity to dissent ahead of the 25th anniversary of a crackdown on a pro-democracy movement around Beijing‘s Tiananmen Square on June 4, 1989.

Gao, who previously worked for state media, was a prominent supporter of the pro-democracy protests in 1989. She was jailed in 1993 for six years on charges of divulging state secrets.