According to this leaked video the former Chinese ambassador to South Korea was once a spy for the ROK:

Footage of a Chinese general discussing sensitive spying cases has been leaked onto Google Inc.’s video sharing site YouTube, in what appears to be an embarrassing failure of secrecy for the usually tightlipped military.

It wasn’t clear when or where Maj. Gen. Jin Yinan made the comments and China’s Defense Ministry did not immediately respond Monday to faxed questions about the video. Calls to the National Defense University where Jin is a lecturer rang unanswered.

While some of the cases had been announced before, few details had been released, while others involving the military had been entirely secret.

Among those Jin discussed was that of former Ambassador to South Korea Li Bin, who was sentenced to seven years for corruption. Jin said Li had actually been discovered passing secrets to South Korea that compromised China’s position in North Korean nuclear disarmament talks, but the allegations were too embarrassing to make public and graft charges were brought instead.

“In all the world, what nation’s ambassador serves as another country’s spy?” Jin said.  [Yahoo News]

Actually this video in regards to Li Bin just confirms what was already suspected that Li Bin was arrested for leaking state secrets in 2007.  The secrets he allegedly revealed was movements of Kim Jong-il to the media.  The next Chinese ambassador to Seoul Ning Fukui may have felt like he had to go overboard to prove his loyalty to the regime considering how the Chinese embassy organized the violent Olympic torch protests in Seoul.