If it is now needed that members of the public need to remind the police to do their job, then theres something very wrong with how we protect vulnerable members of society.
If I had concerns about child sex abuse by a perpetrator living in a different country and I was told by a police force that it would be dealt with and passed onto the relevant authorities then I should have trust that the action is taken by the very people who are put in place to do these things.
I fail to see how I would be at fault for somehow not checking up on police forces in a different to country to the one I lived in to see if they were carrying out their jobs.(not even going into how I would be updated anyway)
My "moral duty" would be ensuring that those tasked with the power to take action were aware. Not somehow making sure they were doing their job it being my responsibility rather than theirs.