HONG KONG (Reuters) - Scores of China social media postings about a well-connected billionaire who went missing from a Hong Kong hotel have been deleted, pointing to what appears to be heightened sensitivity in Beijing over the case of Xiao Jianhua.

A statement of Chinese billionaire Xiao Jianhua is printed on the front page of local newspaper Ming Pao in Hong Kong, China February 1, 2017. REUTERS/Bobby Yip

Mystery surrounds the whereabouts of Xiao, one of China’s richest men who has close ties to some of its leaders and their relatives. He was last seen at Hong Kong’s Four Seasons hotel in late January, with some media saying he was abducted and taken to the mainland.

The case has echoes of the disappearance of five Hong Kong booksellers more than a year ago who had published books critical of China’s leaders.

The booksellers’ case raised concern about interference by Beijing in Hong Kong and the erosion of its freedoms, guaranteed under a 1997 deal that returned the former British colony to Chinese rule.

Authorities in Beijing have declined to comment on Xiao’s case.

Hong Kong’s government has also not commented. The city’s police say they are investigating and have approached Chinese authorities to ascertain his “situation in mainland China”.

Xiao’s disappearance has sparked widespread media speculation that he has been drawn into Chinese President Xi Jinping’s crackdown on corruption, which has ensnared a string of Chinese executives.

After his disappearance, a statement from him appeared on his company’s verified WeChat account saying he had not been abducted and had not been taken to mainland China.

The statement added he was “currently abroad being medically treated”. Hong Kong police say Xiao crossed the border to mainland China.

When news of Xiao’s disappearance in Hong Kong began breaking early last week, searches on Chinese search engines and social media for him generated many results, mostly links to reports related to statements he had issued via his company, Tomorrow Holdings, a financial group headquartered in Beijing.

But those posts and most reports related to Xiao have disappeared, with search results only bringing up reports about him from several weeks earlier.

DELETED POSTS

According to Freewechat.com, which tracks censored or deleted posts on China’s biggest social network, WeChat, more than 40 articles with the keyword Xiao Jianhua had been censored since Jan. 30.

A similar number of reports with the word “Mingtianxi”, which refers to Tomorrow Group and its subsidiaries, were also deleted.

Tencent Holdings Ltd 0700.HK, which operates WeChat, did not immediately respond to a request for comment.

A spokesman for Sina, which runs China’s Twitter-like microblogging service Sina Weibo, told Reuters it censors and deletes posts according to its code of conduct.

But the spokesman declined to comment on any deleted posts related to Xiao and his business ties.

More social media posts purportedly detailing Xiao’s business links with high-profile companies and senior leaders were also deleted over the weekend.

The Chinese government routinely censors the internet, blocking many sites it deems could challenge the rule of the Communist Party or threaten stability.

China’s internet regulator did not respond to a request for comment on Monday.

Shares in firms directly or indirectly controlled by Tomorrow Group slumped on Friday, with Baotou Huazi Industry 600191.SS and Xishui Strong Year Co Ltd Inner Mongolia 600291.SS both down the maximum 10 percent.

Shares of Baotou Huazi were down 2.6 percent on Monday, while Xishui Strong Year was down nearly 5 percent.

Xiao was ranked 32nd on the 2016 Hurun China rich list, China’s equivalent of the Forbes list, with an estimated net worth of $5.97 billion.