I don't think hanging up on the police and calling them back to validate will be an offence... not in my country. So, I would suggest avoiding having a great actor trying to convince you that the police are legit. Either way, the police rarely discuss things over the phone without a physical letter sent to you days or weeks in advance. Usually you have to be the first to contact them, not them to you.
Always verify!
Absolutely right! Thanks, and I will verify. Always!