[villagetinker]

I assume you are asking about the police radios, some time ago 1 or 2 of the top scanner makers claimed to have figured out how to do this and could supply receivers for specific locations. Now as I understand it, the police can change the encryption at any time, and guess what you are now out of luck. There are a few apps for your smartphone that claim to have these transmissions, but the downside is these same apps have been known to have spyware embedded in them. Bottom line it is very hard to listen in on these transmissions.
You can do an internet search, my information is at least 2 years old (last time I did a search), and there may be additional info, but be very careful about any downloads.