BD Police, like many CZ guns, come in small batches here or there. The POLICE model even less so. They used to be super rare for years. Then 6 or 7 years ago, CZ imported them here in pretty decent numbers for a while. Still no where near as common as the regular BD and other models.
I had one of the regular BD POLICE guns I bought 6 or 7 years ago. But it just sat in the safe, so I sold it last year. I do have one rare bird though. Again 6 or 7 years ago, I bought a BD POLICE, but it was a little different. It had all the same features of a BD POLICE, grip checkering, LCI, serrated trigger, lanyard loop. But instead of having "POLICE" written on it. It has front slide serrations. Not a whole lot of these (few dozen?) around. Can in once w/ other normal POLICE. And that's it.
I don't think the BD POLICE have been imported in a while. So secondary market is probably your only option.