The Mortal Instruments in NYC

The Mortal Instruments is filming in NYC with the second unit (no cast).
They probably need to film the setting just to show that it takes place in NY.
City of Bones cast will finish filming in Toronto around Nov. 6th.

Second unit to film MORTAL INSTRUMENTS shots in NYC

With filming on THE MORTAL INSTRUMENTS: CITY OF BONES set to wrap in Toronto on Nov. 6, fans are wondering whether the studio still plans on filming in New York City, where CITY OF BONES takes place.

Cassandra Clare, who plans to remain in Toronto until filming concludes, revealed on Twitter that the second unit will be filming in NYC, which means no cast.

Director Harald Zwart revealed that they are working on the teaser trailer, but no exact time frame is known at the moment only that it’s coming “very soon.”

Once filming wraps and post-production gets underway we will be that much closer to seeing CITY OF BONES make its way to the big screen.

-TMISource

Regarding NYC 'The Mortal Instruments: City of Bones'

Cassandra Clare, who is in Toronto for the remainder of 'The Mortal Instruments: City of Bones' filming, revealed that a a second crew will be filming for the highly anticipated film in NYC. No cast will be involved in these shoots so we can assume it will be shots of the skyline and other sites in NYC to establish the films setting.  

-TMIExaminer