Serena Williams has spoken of her 'devastation and shock' as she urged an investigation into the disappearance of Chinese tennis star Peng Shuai. Fears continue to mount for Shuai, 35, who was once ranked as the top female double's player in the world, who has not been seen since accusing the country's former vice premier of rape on November 2. 23-time Grand Slam champion Williams, 40, publicly called on the authorities to launch an investigation into Shuai's disappearance and urged those involved to 'not stay silent'. She tweeted on Wednesday: 'I am devastated and shocked to hear about the news…