They do? I live there, and haven't seen that.... They are allowed to wear baseball caps in the summer, though!.... You have a link to that?
POLICE BRUTALITY? Woman Says NYPD's First Hasidic Cop Grabbed and Pinched Breasts, Punched Her - FailedMessiah.com
Do you see any of the other officers wearing a hat, as required when they are outdoors? They are all indoors, they required to wear a regulation uniform cap when outside, when inside the Jewish cop's uniform hat is off, as were all the other officers, and he has a "Yamaka" on. Now find a link stating a jewish cop can wear a "Yamaka" instead of a uniform cap!
BUT, I did find this....
Hasidic ex-cop fired by NYPD over beard to argue in court to get his job back
Fishel Litzman made headlines when the top recruit at the police academy was fired a month before graduation for allegedly ignoring repeated warnings about trimming his beard to within 1 millimeter long under department guidelines. Litzman said the NYPD knew about his religious convictions that prohibit him from cutting his facial hair.
http://www.nydailynews.com/new-york/hasidic-ex-nypd-argue-job-article-1.1383512
So you think the Jewish Cop can wear his "yamaka" when it's REGULATION to wear your uniform cap?