I think that it was really strange that in January when BTC went down all big cryptocurrency exchanges closed registration for new members and they opened it only when the price was low. Then at spring when the downtrend was broken(7000$) there were many news that cryptocurrency now will go up! But whales just made big shorts at 10 000 $and all the news said that cryptocurrency won't go up for along time and market went down to current position.
There are people who are manipulating the market price because they want to invest a huge amount in order to earn more profit when the market starts to pump up again in the future.
Actually, I don't think it was manipulated since the price of bitcoin is decentralized but in some possible situation it can be due to those big whales or investors as they can managed the value. Also, it some point those small investors will be affected of their huge losses in times of decreasing and may have a great amount of profit in times of increasing and I believe it may happen in the future though we don't have any idea when it may happen.
No one can really manipulate or control the whole market whales and institutional investors are just a large portion of the market merely around 50% to 60% and the other are the massive small time trader, holder and individual investor. Therefore, the manipulation takes place on our decision if we buy or sell a particular coin and which also affects the market.