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.
Yes, but I so believe that the police do have ways in order to track illegal activities that involves bitcoin as thier medium for payment. We all know that within local bitcoin trading site offer common kyc and this is one of the preliminary measure to help the government on detecting criminals that is using bitcoin.
KYC? As far as I know. KYC is usually used on investing on ICO Projects so how can they know the criminals lurking in there? And do you think that criminals will let themselves send their real identity on the internet where they will know that someone can know him or her? Criminals are not that easy to catch, especially the ones lurking on the internet, we just need to be very careful.
But the truth is, illegal transactions are not associated with only Bitcoin. You can find terrorists being funded with USD, EURO and whatever currency you can think of yet the governments are always on the one arising from Bitcoin. Quite weird, perhaps they have an ulterior motive.