I have seen some news regarding hackers, terrorists, and other criminals using bitcoin for illegal trades.
How the police can find about these transactions?
Even if is hard to track illegal transactions, I don't think that Bitcoin can be a danger to society, since the problem is the society and its people.
Since the beginning of the internet this is happening ( the bad people committing crimes) and no one is willing to shutdown internet because of that, so in that matters Bitcoin should be equivalent. I think those illegal transaction are one of the reasons some governments and the media are trying to depreciate bitcoin, but the problem is not Crypto/blockchain or Bitcoin, is just the society.
It is not about the bitcoin it is about the people who commit crimes. All of us have free will to do anything those criminals are the people who are dangerous in our community not the bitcoin. Even there is no bitcoin there are some crimes that happened in our community. It is the choice of people on how they manage thero life. For those criminals it os their conscience. therefore those who do their job rightly and honestly keep it up guys ffor the bitcoin good identity.