to me it doesn't make sense that price should fall just because CFTC started looking into manipulation! if anything nearly all price movements should have stopped immediately and we should have seen a stable market if there was any kind of fear of this "probe" into manipulations.
what happened instead was that they used this news and a couple of others such as that Asian exchange hack to manipulate prices even more and drop the price another step lower.
In my mind, opened price manipulation probe is an formal excuse to be used by CFTC to accelerate introduction of strict crypto regulations & to strengthen control over cryptoexchanges.
this is not a bad thing though if you think about it. we all know that the cryptocurrency exchanges have never been trusted places for traders to go and do what they do. we have seen enough scams and runaways in the name of "hacks" that we actually need strict regulations if you ask me. and if done right we may even see an increase in adoption of bitcoin since a lot of people are scared of using shady exchanges to buy bitcoin but they will feel a lot better using a regulated and more trusted place to buy bitcoin.