From The Epoch Times (link):
In the spring of 2006, a student club at a prestigious university in Shanghai City broadcasted a film on campus readdressing the 1989 June 4 Tiananmen Massacre. After the broadcast, the student club distributed pamphlets and setup a website. Over 100 people participated in this activity. An insider disclosed to The Epoch Times that this student club was likely to have been set up by students at either the Shanghai Jiao Tong University or Tongji University.
Somebody secretly reported the students’ activity to the Chinese Communist officials. As a result, the next day, the president and the vice president of the club were arrested and the website was blocked. The parents of the two students went to school to see their children and complained with the student office. One day later, several students joined to express support, hoping that they will be released.