The Beast took over very simply, but Harry didn't stand on it's way. This cop's blood was the blood Harry enjoyed the most, so the Beast was happy. Too bad he ended too soon, leaving Harry still too hungry to feel straight. He turned back and found another body in the uniform, bleeding with vitae all over the warm asphalt. Harry sank his fangs into this poor bastard's arteries, taking what was left in him. But this one was also almost empty! Well, bummer.
The monster in human flesh straightened, without a rush, and turned around. Nobody was already there, and only a dotted blood trail led somewhere further into the streets. Harry followed the path, and started his pursue of the wounded vessel. The blood was fresh, the vessel was close, the Beast exulted. Harry found the last cop laying alone in the middle of the pedestrian street with nobody around. He drank the last drops of vitae from this vessel and finally started to cool down.
The city was empty, like in zombie apocalypse.
There was another cop though, the last one. Although he wasn't wounded, he couldn't have gone too far.