Actually the only reason BTC went down after that was emotion. Silk Road's effect on the price was like a fly on windshield - zero.
BUT I will say that other more organized and nefarious groups, like those often associated in movies with Italian heritage, could be keeping more in BTC than anyone cares to imagine. But they don't build websites and attract attention of the public. IMHO
That's actually a really good point that I hadn't considered.
If I was on the dark-side I would definitely store and move money in BTC. So much easier than fiat from whatever country.
I actually thought that was one of the theorized reasons for the spike in BTC ($250 at one point) during the Cyprus banking crisis. Cyrpus banks have long been a parking spot for Russian Mob money due to their poor oversight. One of the potential solutions to the crisis was the government was going to seize a percentage of everyone's account to bail out the banks. When that was announced BTC soared. If I recall properly. That was the Mob moving their funds to BTC instead of getting a percentage seized.
Someone is probably more up on the details than me though.