UCLA Film & Television library has some episodes of the ABC television series "N.Y.P.D." that can be viewed on site. A series running from 1966-69, the show was filmed in New York, apparently in that "gritty documentary" style. Starred Jack Warden, Al Pacino was in one episode. 

This series paints a tough, realistic portrait of the work of the New York City Police Department. Filmed on location, N.Y.P.D. utilizes the highly mobile hand-held camera and stream-of-consciousness narrative. Tonight: Lt. Mike Haines and his two partners, Dets. Jeff Ward and Johnny Corso, investigate a blackmailing ring that specializes in extorting money from homosexuals"--TV guide, September 5, 1967.

UCLA record: 

http://cinema.library.ucla.edu/cgi-bin/Pwebrecon.cgi?v1=2&ti=1,2&Search%5FArg=N%2EY%2EP%2ED%2E&SL=None&Search%5FCode=FTIT&CNT=50&PID=1Mo0rGFfvsH4HgTJvewnZhMjxo7kTbs&SEQ=20091209142653&SID=1