Well, I don’t know in the US, but there is a Police Intellectual Property Crime Unit in the UK.
Moreover, 2 or 3 years ago, the City of London police has placed advertisements on websites that offered pirated content illegally.
It seems that the same kind of police exists in the US (https://torrentfreak.com/u-s-anti-piracy-police-kept-secret-from-the-public-110811/)
So maybe it is not as obvious as that…