After a Chinese professional tennis player accused a former senior government official of sexual assault, she has disappeared from the public eye—and Chinese feminist groups along with global tennis stars are sounding the alarm. The Guardian reports that Peng Shuai, a former doubles pro, alleged earlier this month that former Vice-Premier Zhang Gaoli sexually assaulted her, in a Weibo post that China’s censors promptly took down. Despite the censorship, which included banning keywords like “tennis,” the post still went viral. Amid the tennis star’s radio silence, Chinese activists have put up projections on the side of various buildings that read “Where is Peng Shuai?” and “We demand Peng Shuai’s safe return.”

Though the Chinese Tennis Association alleges Shuai is “safe and not under any physical threat,” her silence has pushed international tennis players to speak out, including the former world singles master Chris Evert. “I’ve known Peng since she was 14; we should all be concerned,” wrote the tennis star. “This is serious; where is she? Is she safe? Any information would be appreciated.” Steve Simon, the chief executive and chair of the Women’s Tennis Association, has called for a “full, fair, and transparent” investigation by the Chinese government and asserted that “all women deserve to be heard, not censored.”