My guess is, that it was chained there without being moved over a relatively long period of time, and the proprietor of whatever is in the building got sick of looking at it.
The other possibility, seeing that barrier on the left, is that it's a parade route and the cops want it out of there, and couldn't find anyone who said it was theirs. NY has more parades than any other city I know of. Those moveable barriers are for crowd control.
The tool is probably some kind of power saw. The police vehicle is an ESU van (Emergency Services Unit) and those saws are used, among other purposes, for cutting trapped motorists out of crashed cars. The FD used one that had a particular brand name that they called it by, but it's been a long time since I left that looney bin of a place.