There's a rumour the Bank of China has demanded all Chinese exchanges close their trading accounts by April 15.
Not confirmed, but that's how speculation goes.
I saw it as it was happening but didn't take any screen shots. A few hours ago there was roughly $3m in bids between the price going below $400 now there is only about a $1m
The rises and falls in BTC are news driven. Turns out every "rumour" about a crackdown on BTC in the past has later turned out to be true, see my last post in this thread.