We're going to go out on a limb here. There was a wild shootout (in Jersey City you say incredulously) with a feller on a bike shooting into a crowd and at least one person in the crowd had a gun and shot back and killed the bike rider. Now, not wanting to get too far out front of the story the Jersey Journal reports:
"The exact cause of death would be determined by an autopsy to be performed tomorrow..."
Again, going out on a limb we're going to guess and say the fact the biker's body had significant deceleration trauma from stopping hot lead traveling at 1100 feet per second did him in. That's just us...
Time for Jersey City, After Dark