I don't think that has happened but it may be true as well. Jemie is a smart banker. It may be possible that he tried to bring down the price by saying that bitcoin is a fraud and then bought a good amount of bitcoins at a lower price. Anything can happen in the corporate world. This kind of manipulation is very common around the stock market.

However, I doubt that JPM will ever invest in crypto coins because I believe that the legal status in USA is still unclear. So a bank will never take such regulatory risk with public money. It may be just a rumor.