This is a quote from Wikipedia:
"In British English, it is generally accepted that collective nouns can take either singular or plural verb forms depending on the context and the metonymic shift that it implies. For example, "the team is in the dressing room" (formal agreement) refers to the team as an ensemble, whilst "the team are fighting among themselves" (notional agreement) refers to the team as individuals."
However "the police" takes the plural form of the verb (have/are). The sentence is correct.
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