China Kills/Imprisons 20 CIA Spies in 2 Years

China was able to achieve a ruthless purge of CIA informants from its govt, to cripple US spying operations against it:

https://www.nytimes.com/2017/05/20/world/asia/china-cia-spies-espionage.html

From the final weeks of 2010 through the end of 2012, according to former American officials, the Chinese killed at least a dozen of the C.I.A.’s sources. According to three of the officials, one was shot in front of his colleagues in the courtyard of a government building — a message to others who might have been working for the C.I.A.