“Police” usually refers to more than one person, so it is usually “notionally plural”. For the word “police”, this is even true in American English, which usually avoids the notional plural in favor of the “formal” singular. For example: British “The band are playing well tonight”* versus American “The band is playing well.” Note that the words policeman / policewoman / police officer are singular, and can be made plural in the usual way. Other singular words are: the police department, the police force, etc. *Note: UK speakers sometimes use the singular, if it is notionally singular.

In America English I would say like the police came. Which that doesn't mean it was 1 officer or multiple. The police are here. I also don't know many times where in America you encounter one police officer it's usually two so maybe thats why I'd just use the police. Like others said if it's one you can say police officer.

“Police” is plural, it means “the collection of police officers”. You can use “police officer” for singular and gender neutral word.

What do you mean?