Why is "police" referred to using the singular pronoun "it" in this sentence?

Solution 1:

Singular the police seems to be very common in Indian English journalism.

Googling “the police have” and “the police has” with “site:indiatimes.com” yields claims of 1,430,000 hits for the plural and 525,000 hits for the singular—and on a quick “eyeball” survey the singular hits appear to be only about 5% or 10% false positives like “trust in the police has been shaken”. “site:hindustantimes.com” yields 246,000 for the plural and 32,000 for the singular, and “site:tribuneindia.com” yields a 7:1 preponderance of singular uses: 176,000 hits against23,000 hits on the plural.

Solution 2:

This site gives a good reasoning on why collective nouns are used in singular and plural ways.

The police act as a single unit in the news report, so their actions are as a single unit. If the police were acting individually, then they would be referred to in the plural

Solution 3:

In addition to the other reasons presented, the term Delhi Police is a proper noun that is essentially a shortening of the Delhi Police Department, which normally would be spoken of in the singular.

Similarly, you would say "Customs has cleared my package for export." Even though Customs is clearly a plural word, it is functioning as a short form of the Customs Department.