I am often asked at seminars about law enforcement and HIPAA. My answer is usually to provide the attendee with a copy of the Washington State Hospital Association's Hosptial and Law Enforcement Guide to Disclosure of Protected Health Information, which is 33 pages long.
The short answer is that law enforcement and healthcare workers have different priorities, and I give a warning that the cops will cheerfully lie to you about their authority if they think it will help them to catch the bad guys. I would to, if I were in their shoes.
An example of how this might play out in your state can be found here, where, predictably, law enforcement wants one thing, and healthcare folks want another. Nearly every state has already addressed this problem, but once again, it isn't the overworked cop's responsibilty to ensure your compliance, it is your overworked staffer's responsibility.