Police activity on Prospect btwn Vanderbilt Underhill

Low-flying police helicopter around 5:45 PM Friday 10/18 and many police cars going against traffic every which way. Also, an ambulance and blocked street on Prospect between Vanderbilt and Underhill. What happened??

I walked by around 5:55 and like 25 cops were on the block and a cop was in the back of a car getting oxygen. I asked people on the st what happened and they said there was a chase. Someone mentioned something about someone climbing on a fire escape, but no one seemed to know the story.