Guo, who left China in 2014, is an outspoken critic of the country's Communist Party. The New York-based tycoon's unsubstantiated accusations against top-tier Chinese officials on Twitter and YouTube have garnered him quite the social media following. For its part, China has issued a global "red notice" through Interpol for Guo's arrest. Although the exact charges against him remain unclear, the country's state-run media has previously accused him of bribing a vice-minister. And, in August, Chinese police opened a new investigation against the billionaire on rape charges. Guo is also facing a series of defamation lawsuits in the US from various Chinese individuals and companies. He denies all the allegations against him.

China is no stranger to charges of state-sponsored hacking. Last year, the Federal Deposit Insurance Corporation pointed the finger at the Chinese military for a spate of cyberattacks launched against it since 2010. And, in August, the FBI said it had arrested a Chinese national linked to the massive data breach that struck the Office of Personnel Management back in 2014 to 2015.