You might want to read the CVR transcript from the EgyptAir990 mishap.
Yes, I am aware of the transcript, and that all evidence indicates pilot suicide. I didn't say that the US weren't correct in that instance.
One of my points is that the Malaysians may not want to lose control of the 'investigation', for several reasons. Ceding control to the US bodies while apparent leaks are still occurring? Not very attractive.