A missing Chinese businesswoman with links to senior Communist Party officials and their families has reappeared after four years, according to her ex-husband, who has written a new book about her controversial business dealings.

Duan Weihong, also known as Whitney Duan, was one of China’s wealthiest women. She disappeared in 2017 following reports she set up companies and facilitated investments with relatives of Wen Jiabao, who served as China’s Premier between 2003 and 2013.