A tip to the unaware or unfamiliar in dealing with the police: first of all, know who the police are! Know the difference between the city police, the county sheriff's department and the state troopers. They have slightly different but overlapping jurisdictions. Their cars are probably painted differently and they probably have different colored uniforms. Know who your primary service provider is! If you live near the border of your jurisdiction, know what the uniforms and the squad cars of the neighboring town look like. That isn't too hard -- just pay attention when driving around on your normal business, and then remember what you see. Neighboring jurisdictions back each other up all the time, and if one agency gets tied up on a major incident, the department next door may end up being primary responders to calls in that town. It happens all the time, and it is NOT evidence of a particular emergency nor of a government conspiracy . . .
If you live in Hickory Hills and the Police Communications Center gets a 911 disconnect from your house, you may get the Hickory Hills PD or the Sheriff's Department or the State Police or cops from the next town or village over, depending upon the situation. It's not at all unusual.
Any time you interact with the police, be truthful, don't have an attitude nor appear to be concealing information and your day will go a lot smoother. Almost always when we the police encounter somebody with a belligerent attitude, it's because they're trying to hide something. You don't have to offer information, but answer the legitimate questions that you are asked. If you appear to be trying to hide something, cops treat that the same way that sharks treat the smell of blood in the water . . .
Just because you explained something to the call taker on the phone DOES NOT mean that information was ever passed on to the officer. If it’s really busy, they’ll just send the officer with a minimum of information and expect them to sort it out when they get there.
If you live on the boundary of multiple jurisdictions, be aware of where the incident happened and which police department you called. If you have called to report an incident, and then just flag down a passing police car, the cops inside (a.) may not have received the call yet and so have no idea what you’re talking about, or (b.) may be from another jurisdiction, possibly dispatched by a different comm center on a different radio frequency, and they may not know what you’re talking about, either.
Just because you talked to a cop once about a particular situation does NOT mean that all cops everywhere will be familiar with the situation. We are not telepathically connected!
If you reported a problem at midnight, don’t call back at eleven the next morning and expect to talk to the same officers. Individual police officers are not on 24/7. We do go home to sleep and conduct our personal lives from time to time.
Pay attention to what agency the officer works for, and ask for their name and badge number or radio number or ID number. We get issued business cards to give to people we interact with. Get a business card from officer friendly and ask for the case number of the incident (if there is one), the address of occurrence and the case title, and write down the date. That way, if at some later time you need to make an inquiry, you'll have the information that you need.
If they’re in plainclothes, feel free to ask to look at the officer’s credentials. Just keep in mind that you don't know what an authentic police ID card for that agency looks like. (I don't know what official ID cards for the surrounding agencies look like, either.)
If somebody comes to your door in plainclothes, and they're a real cop, they're used to having people ask to see an ID, and may be used to having you phone dispatch to verify their identity, depending upon where you are. BE SURE YOU CALL THE RIGHT POLICE DEPARTMENT!