I'm from NYC and have been following the story all day. It appears that a politician was killed by a rival who couldn't get his petition in on time to receive campaign funds.
It just amazes me how easy it is to infiltrate City Hall with a gun. All you need to do is be nice to the security guards for a couple of days and you're in.
I was glad to hear that it wasn't related to terrorism. Had it been so, there would have been a riot.