[Doc Faustus]

Spoiler

Though I have never seen the film, I will do my best to answer your question. When the overweight black cop shows up to check out the crime scene, the brother sprang back to life and bit him, turning him into a wereclown, which the brother had been turned into by clown exposure and therefore left for dead, since there's an incubation period. This paves the way for the sequels.