maybe they tried to spread negative news about bitcoin and once it is down in value, they will buy it and wait for it to rise again and they have big profit. That is how big and not so good investors are manipulating the market in their favor and also some insider trading.
It wont affect the price of bitcoin if just one person spreads bad news about it, even a lot of person does that and doing it everyday but that is not having any affect on the price, but it surely affects the user database of bitcoin as the ones who hear that bad news or rumors never join bitcoin.