The hip hop police is a term used in the hip-hop industry for an NYPD department devoted to criminal activity within the Hip-Hop industry. Originating in New York and spreading to Police Departments of several cities. They are obviously mocked and disrespected within the hip hop industry for their overly aggresive investigations and constant stalking of high-profile rap artists. Usually the hip hop police don't take in artists to jail but offer them a deal to say a few names and they will be let go. Which unfortunately if you haven't noticed not many have been to jail as of late.
Quote from 50 Cent off the track "I Don't Know Officer" from the Get Rich or Die Trying Movie Soundtrack.
"ah, I don't know nothin 'bout dro or hash
Coke, dope, ex, dust or crystal meth
Nah, I'm just tryin to rap to get some cash
Keep the Hip Hop Police off my ass"