Not completely. How many video files does he have? Where is it stored?
I'm curious now though, do Truecrypt volumes have a magic number, in which case it's still easy to find, or are they fully crypographically random in appearance, making this a known-needle in a large haystack problem?
Truecrypt claims an encrypted volume is indistinguishable from random data. I do not know if this is the case though. Obviously don't give it the file a stupid name or extension like "encryptedfiles.tc" or leave it open in your file history, etc.
It's also pretty suspicious if someone has a file of megabytes of random data.
