>you're dead wrong - we always use 'are' with 'police', not 'is' -
>it's an aggregate, not a collective noun (just like cattle, people)
people Show phonetics
group noun [C]
1 all the men, women and children who live in a particular country:
The French are known as a food-loving people.
zobacz w słowniku cambridge.
Poza tym z 'police' też może być 'is'.
Not always is it an aggregate as you may see.