You seem to be confusing the International Court of Justice (ICJ) with the International Criminal Court (ICC).
On the other hand, I think my point about national attacks on supranational institutions remains relevant.
The EU isn't a court, and European institutions (including European courts like the ECHR) are particularly not "higher courts" over police in the US. The ICJ hears only cases between state parties, not between states and their subjects, and the UN isn't a court at all, and, again, is only a forum for state parties, not for disputes between individuals and states, though sometimes you can get a state party to stand up for subjects of another state; but, that's not really much of a practical option if the offending state is the US, both because of its Security Council role (which Uniting for Peace, in theory, provides a route around through the General Assembly), and because of its hyperpower status (which means that there is, in practice, no way to enforce a decision against it, even if one was reached through UfP.)
You don't doxx police officers and paste their IDs online. The chance you're taking, the certainty indeed, is that someone will follow through (perhaps even an agent provocateur) providing the justification for waves of ruthless revenge.
Nope, you bring your dossiers to a higher court and ask for Justice (EU, ICJ, UN.)
Edit: unless of course the situation has deteriorated so badly that the prospect of civil war with all its casualties and pain is on the table.