Police police police police police police police police.

Try interpret the captioned complete sentence and see how it can be further expanded.

Solution:

The first word Police is a proper name, such as the name of a city. You can use it to further expand the sentence, noting that the word police can be both noun and plural verb:

Police police (whom) Police police police police Police police (whom) Police police police.

The word in bold is the verb of main sentence.