<Conspiracy Theory>
If this is something caused by the NSA or some such agency, they may also be under some “gag order” like restraint and are not free to talk about any of the dealings at this point.
After reading this article and hearing the method/tactics used, Why Lavabit shut down: Founder explains 38 days of legal hell, I can only imagine what could be going on and can understand for the abrupt shutdown of TrueCrypt!
It may also be a form of protest, if they are not allowed to talk about it. It has brought up speculation and is getting people talking & thinking about security and privacy a bit more.
I hope I didn’t get too political for the forum…
</Conspiracy Theory>