I don't quite get these comments, I think our emergency services went encrypted a while back in Vancouver Canada and I'm surprised NY wasn't already encrypted?
What about keeping the communications encrypted for the privacy and safety of people involved, and storing the records for a set amount of time. Anyone with access to the live feed can access the backups during that time, and report issues as needed.
I'm not familiar with the issues with the police department, so maybe a better compromise would be to open up the feeds publicly after a set amount of time?