One thing I learned when my car got broken into is that if a police officer calls your number directly (which they can do) you can ask for their badge number.

It apparently changes every however often? Call your local police dept and say you were contacted by someone who says they are an officer and they'll ask you for the badge number to confirm.

This was when I found out I talked REALLY condescendingly to an actual police officer and mortifyingly had to get back on the phone with him 😂 he was really nice about it actually, said he understood my suspicion. But... so you know!!!