Supporting character. Only 2 lines-- though they're important ones, and the final words in the film.

Just a guy doing his job. A police officer who arrives at the scene after Joey, panicking, calls 911, reporting a man with a gun. The situation seems simple to his eyes: there's a delinquent to apprehend, and a frightened victim to comfort. He takes charge of the latter, unaware that Joey's disquiet is driven as much by guilt as by fear.

Although he intends for his words to be reassuring, they come out more than a bit ominous with the context that Joey has been safe all along-- but now, Mack very well might not be.