The baffling disappearance of Chinese executives in recent weeks has drawn attention to the ruling Communist Party's practice of holding people incommunicado either as targets of investigations themselves or to help with probes of others.

The most recent example came Thursday, when Caixin magazine reported that Guo Guangchang, the billionaire chairman of Fosun International Ltd. couldn't be contacted. Fosun suspended its shares Friday and its bonds plunged by a record before the company said Guo was assisting justice authorities with a probe.

Other high profile cases in recent weeks included two members of Citic Securities' executive committee who became unreachable earlier this month, along with Yim Fung, the chief executive officer of Guotai Junan Securities Co.