Grenade!

Yesterday, at 3:30 in the morning, somebody threw some crude grenades in front of the British Consulate in New York. The explosion blew out a window.

There's a security-camera video of the event.  It shows a bicyclist, a female jogger, and a taxi.  A female jogger at three a.m.!  That's a good example of why they call it the City that Never Sleeps. 

Anyway, the police are hoping these people will come forward as
witnesses.  But they haven't.  Either they're all in on the
grenade conspiracy, or more likely the famous New Yorker "don't get
involved" philosophy is in force.

I've lived in New York.  A lot of people there are not like
that.  But you hear "don't get involved" a lot more in New York
than in Chicago for some reason.  I'm not sure why.

How can a case be solved
If no one will get involved?