As has been pointed out since the salaries are not high enough to keep pilots employed on a permanent basis in Police aviation there is always a need for new pilots and this means you also can get employed with 1500hrs and no
real low flying experience. From what I have seen it depends on many factors why they might employ a "risk" without the textbook experience. I would maybe call it a mixture of desperation and forward thinking.
If it's your dream to fly for the Police one day don't let anyone stop you!!!!!
What you do need is experience on twins and night (single or twin) flying onshore.