When Yang Xiuzhu got wind in 2003 that Chinese anti-corruption investigators were looking into her affairs, she boarded a flight to Singapore. A few days later Yang changed her name and flew to New York.

China filed an arrest warrant through Interpol for Yang, a senior official who oversaw construction projects in the booming eastern province of Zhejiang. She was eventually detained in Amsterdam in 2005, but nearly a decade on, China has yet to get her back despite protracted negotiations with the Netherlands.

Yang's case and others like it underscore the challenge for President Xi Jinping as he expands his already far-reaching anti-corruption campaign to tracking down suspects who have fled abroad, often taking their ill-gotten gains with them.