West 164th Street is a Bloody Mess

I was walking along West 164th Street in Washington Heights this morning, when I happened upon the aftermath of a really nasty fist fight, or some sort of savage beating-up...

Aside from the large splatters of congealed blood: the blood-encrusted remains of someone's wristwatch, and on the right... is that part of the plastic hand grip from a pistol?

Blood was splashed on two cars parked by the sidewalk...

The entire scene was gruesome. What happened here?