It was flying over the South China Sea enroute to Beijing and was shot down by mistake by the US Navy who were doing active pinging of China's defenses at that time.
A new story that it turned around and flew off to the only area on the planet not under surveillance, down from India, towards Antarctica was invented to cover the shoot down mistake.
The full investigation was handled by the PM of Malaysia. Within the month the US President, Obama, flew to Malaysia and offered a really good trade and military deal to Malaysia that they happily accepted, and at that same time the Saudi Royal Family gave the Malaysian PM US$800 million as a free gift because he was a nice man.
