At least 870,000 bitcoins are associated with illegal activities. This is about $ 10 billion.
900000 BTC is around 4,25% and more of the total supply of Bitcoin 21.000.000.
Well does it really influence the market with that percentage? Moreover, will they enter the market suddenly at one time?
We don't even know where the BTC is now and we also do not know whether they still keep the BTC or turn it into cash. Probably they are some of the whales. but probably they are also using it only for converting to cash money easily in order to make some certain payment.
So, I think that it will not bring a big significant influence to the market.