The revelations that China has managed to produce a stealth fighter by reverse engineering parts of a downed f-117 US fighter in Serbia made me think.
I don't like conspiracy theories, but as a historian I can connect the dots to raise great suspicions about the total annihilation of the Chinese embassy in Serbia in 1999 by US ordinance. At the time president Bill Clinton first claimed it was accidental, but the guardian claimed that the bombing was deliberate claiming it was to stop the Chinese monitoring of US cruise missile capability and thus prevent them from developing counter measures.
At the hearing about the attack the head of the CIA has admitted that this was the only strike that was authorised and directed by the CIA in the whole conflict.
Even at the time it was considered that the Chinese were making deals with the Serbian government to acquire the parts of the US (no so) stealth fighter. We may never know the truth but circumstantial evidence seem to build a significant case that NATO intentionally bombed an embassy:
1) Downing of F-117 stealth plane March 28, 1999, using simple modification of 1960s SAM site technology
2) May 7, 1999 bombing of the Chinese embassy
3) Acceptance that this was the only operation made by the CIA
4) Acceptance that the story about having the wrong address were not accurate by the CIA
6) New smokescreen put up by the US army about Chinese relaying Serbian Military messages
5) Rapid development of Chinese Stealth fighter - based (apparently) on parts from the downed F-117
So it sees quite likely that the bombing was made by the CIA in an attempt not to allow China delicate technology. It seems very unlikely that this would have the go ahead of President Clinton as bombing an embassy is not to be taken likely.
No doubt this should be investigated further. Since Serbia and Nato were in an (undeclared) state of conflict, the Serbs had every right to sell any captured technology to the highest bidder. The bombing of the Chinese embassy is illegal and in violation of several international treaties, and raises the question about the morality of the US in War.