This is theoretically possible. You just need to be super rich and you can affect its price dramatically. So, any one from the top 100 richest can do such control easily.
May be Buffet of Amazon's jiff.
It may be possible, but there is still no proof that this kind of thing is really happening.
Finding a proof for this information may be a bit hard, and if there is really someone controlling or manipulating the market, it might affect the whole market if discovered.