If this is an issue with Civs tackling Police (Which I don't even think is possible) then be sure to reach out to a Senior Civ to report the incident. If its an issue with the police tree, go to a TL for the division of whom you are reporting.
Moreover, the AI dogs for DSU simply cannot stop Civs or bring them to the ground, it would be amazing if they could. They just simply have small text above their model "Woof. Woof" and I can tell you now, 95% of the Civ division don't know that is their que to get on the ground, not even I did until just recently. Hence DSU tackle people rather then send the dog to finish the job because they simply won't.
Hope this helps? If not feel free to explain further